Synopsis.

(1) Various sorts of causality; selection of efficient causality for special treatment.

(2) The opposition made to efficient causality, (a) on the part of "Occasionalists," who allow its reality; but attribute it directly to God, and (b) on the part of pure Empiricists who deny it to be a known reality.

(3) Proof (a) that there is efficient causality in the world, and (b) that this causality is not divine but mundane.

(4) Explanation of some statements about efficient causality, which need clearing up: (a) "The effect is like its cause." (b) "The cause is prior to its effect." (c) "The same cause under the same circumstances has always the same effect." (d) "On the cessation of the cause the effect sometimes ceases, sometimes not." (e) "A cause is more than a condition."

Notes and Illustrations.

(1) A WIDER term than cause is principium, or principle, which is defined to be,^{1} "that from which anything in any way proceeds," whether the bond between the two be intrinsic, or only extrinsic; whether it be real, or only logical. In Logic the premisses are the principles whence the conclusion follows; in the order of knowledge they are theoretically supposed to stand first, and it comes after; but in the order of real sequence it may very well be the other way about, as when from observed effects we infer the producing causes. Here, how ever, we have not to treat of logical "principiation," But of real.

The order of priority is three-fold: it may be that of mere time, as when January the 1st, according to our calculation, is called the principle whence the year starts: it may be that of nature, in which priority of time may or may not be included, as when the essence of a creature is said to be the principle of its "propria," that is, of its peculiarly inseparable attributes, or the soul is said to be the principle of life in the body: and lastly it may be that of origin, a name devised to express that the Father is principle of the Son, and the Father and the Son form the joint principle of the Holy Ghost, without any priority or superiority either of time or of nature.

Principle, as expressing priority of nature, leads us to the general idea of cause, which is defined, A principle which by its influence determines the existence of something else: or a principle which in some way furnishes the ground for the existence of an object; a principle which of itself gives birth to something else.^{2} In some cases the otherness of the effect from the cause is obvious: but there are also cases in which it is not so unmistakeable, because the cause enters in as a constituent of the total result, which is called the effect. Yet in all cases, without exception, St. Thomas^{3} insists that there is an otherness in the shape of some perfection produced: hence a thing that is simply self-caused, according to our definition of causality, is an impossibility. If ever God is styled the cause of Himself, the phrase is an inaccuracy; we should say God is self-existent, or is His own sufficient reason. Moreover, His immanent action is quite identical with His substance, and has therefore no strict causality; His thoughts and volitions, for example, viewed apart from any external effect that they produce outside God, are thus identified with the Divine Essence: whereas in the immanent action of creatures the agent as agent is distinguishable from the agent as patient. We distinguish the soul as productive of thought from the result, the soul as informed by its own thought: but what precisely the distinction is Psychology must say.

Though Lewes has declared the four Aristotelic causes to be "not verifiable, inadequate, and unscientific," we must take leave to set aside the verdict as not sound. Reid^{4} had previously objected against them that they could not be called causes for want of a common generic concept, to which difficulty Hamilton had replied that "they have this much in common, that each is an antecedent, which not being given, the consequent called the effect would not be." Our sufficient reply is, that each comes under the definition which we have assigned to cause in general, as that which is a principle of Being to another, or that upon which the Being of another depends.

Material and formal causes are such, that each contributes itself as a constituent of the whole which results from the union of the two. Not by mere mutual interaction, but by mutual self-communication, they combine to produce the total effect; so that if the subject is said to support the form, this support, though grammatically it is represented as an action, is not physically an action in the ordinary sense of the word, as when a pedestal supports by its action a statue. Accidental unions of the kind are such as those between marble and its form in a piece of sculpture, and between the mind and its thought: while the connexion of soul and body is an instance of substantial union between matter and form. No mere presence in space or dynamic interaction will suffice for such union: the two causes are constituent, not efficient. Nevertheless, not all constituents are straightway to be ranked as matter or form in relation to one another: but only such as stand to one another as recipient, determinable subject, and determination received. That relations of this kind are entered upon so as to produce definite effects cannot be denied, and practically is not denied, even by those who theoretically ridicule the whole conception of matter and form; the only controvertible question is whether the schoolmen have pushed the idea too far, and such controversy is out of place here.

It is impossible to explain at any length material and format causality without entering upon Special Metaphysics: and therefore we must rest content with indicating two of the questions which will be found to have received due attention in other treatises; in Cosmology the discussion about the ultimate constitution of matter, and in Psychology the discussion about the substantial union between man's soul and body, bring out pretty nearly all that the schoolmen have to say on matter and form.

The final cause is another subject which receives its fullest degree of attention in the treatise on Natural Theology. There, under the heading of the Argument from Design, authors inquire what evidences of a planning mind are to be discovered even in the physical univerre; whether all the laws and the harmonious working together of the material elements to constitute a cosmos, can be ultimately attributable to blind forces acting uniformly through. out indefinitely long ages. Again, philosophers frequently discuss whether vegetable and animal^{5} organisms have risen up spontaneously and without foresight, or whether they point irresistibly to an intelligent Creator. Lastly, the finite intelligence itself is taken into account, and the inquiry is made whether it originated out of blind elements without design on the part of some Supreme Intelligence. This sketch is enough to show how completely the subject of teleology is discussed in the scholastic system. If we start from the most certain testimony of consciousness, it is thereby put beyond reasonable doubt, that we are induced, by ends which we propose to ourselves as desirable, to carry out even long series of works in order to achieve such ends. They clearly are causes in our regard, not because they compel our efforts, but because at any rate they solicit them, and call forth our energies, which would remain inactive if there were no solicitation brought to bear upon them. When a man, who perhaps otherwise would have been a sluggard, makes it the struggle of a lifetime to carry out his fixed purpose of becoming Prime Minister of England before he dies; when one who has spent half his days in idle luxury is suddenly roused to intense activity in order to repair the fortunes of his house which he has ruined, it would be a lamentable sacrifice of truth to some pet theory if certain philosophers persisted in maintaining that final causes had no real influence. So real is their influence that we may call them even efficient causes, if only we remember that their efficiency is of a peculiar character -- one which is adapted to the manner of acting proper to a moral agent, who is moved not physically, but through his intelligence and will. It is no part of the doctrine of free-will, as adversaries sometimes suppose,^{6} that it maintains motiveless action; on the contrary, it holds that motives are quite necessary, and that freedom consists in following the call of one motive in preference to another. The error is rather with some of the opponents of free-will, who while they scout the notion of motiveless action, yet deny that motives, when regarded precisely as intellectual motives, have any causality. Mr. Huxley considers it probable that the conscious phenomenon in man is a mere concomitant of the choice, in no degree a determinant. We take up the position that final causality is absolutely demonstrable from an analysis of our own conduct, about which we cannot be deceived.

Final causes include the main object at which we aim, or the end to be reached (finis qui); the actual possession, or the actual production of this object, accordingly as it is a finis possidendus or a finis efficiendus, a goal to be reached, like the summit of a mountain, or a work to be accomplished, like the carving of a statue (finis quo); and lastly, the person for whose sake the object is sought, whether thisbe self or not-self (finis cui, or cujus gratia).

The exemplary cause is such as guides the artist in the execution of his work, whether it be the copying of a masterpiece, or the realization of an original conception. God who created all things, not unintelligently, but according to His own prototypic ideas, used these as exemplary causes. These may also be regarded as formal causes, if we remember that they are extrinsic, not intrinsic, to their matter.

But our chief concern in this chapter is with efficient causality in the strict sense, as defined by Aristotle, "a principle of change in another." The definition is variously reproduced thus: "That which by the activity of its powers makes something to be which before was not;"^{7} "That which transfers from non-existence to existence what was incapable of self- existence;" "That from the real physical activity of which the production of something follows." To defend this definition will be our task: but we will premise a few points of detail, not indeed necessary to our main object, but still useful. One observation especially deserves attention, namely, the relation of efficient causality to the chapter on Possibility. In that chapter what we called intrinsic possibility mainly engaged our attention, and of extrinsic possibility we said very little. The treatment here of efficient causation supplies the previous omission.

Answering to every action is a corresponding passion, at least if we leave out of account simple creation from nothing, where in reference to the whole object the passion is metaphorical rather than literal. Again, action is transient or immanent according as it passes out of the agent or abides in it as in a subject: the action of one billiard ball on another is transient, the action of the thinking faculty is immanent. In both cases, though in less degree for one than for the other, the schoolmen assert some distinction between agent and patient; because even in immanent agency, the agent as active and productive must be somehow different from itself as passive and receptive. It is an opinion, which St. Thomas at least in certain places approves,^{8} that the action and the passion, are the same thing under different relations; the action is the effect as dependent on the cause, the passion is the same effect as received by the subject. At this point Suarez^{9} has a subtle argument whereby he wants to establish a modal distinction between the action and its term: but this is a delicate question which we may leave for defter hands to manipulate, as our broad inquiry turns on much more tangible pivots. If however it is remarked upon as strange, that by the above theory we have as a result that the action is in the patient, the schoolmen reply that under one aspect it is, in another it is not: as that which is produced and received into a subject, the action is in the patient; but so far as the agency producing and communicating the action belongs to the efficient cause, the action was in the latter potentially. Suarez further teaches that by acting the agent qua agent, if we regard the matter in ultimate analysis, makes no change in itself, but only in the patient. To do justice to this assertion we must observe that it does not exclude the facts so obvious, at least in material changes, that every action is repaid by reaction, so as to make every agent also a patient; and also that in a complex agent one part acts upon another, so as notably to change the agent as a whole.^{10} For example, in severe bodily labour man in his entirety undergoes many changes. But to understand the aspect from which action works no change in the agent as an agent, we should have to take a simpler case than ever our rude experience brings us across.^{11}

From these subtleties let us pass to the more tangible matter of dispute. We have to settle whether that on which all science ultimately rests, namely, efficient causality, is real: and the subject is so vital that Hobbes was near the truth when, as he tells us, it dawned upon him quite in a startling light, that the most important philosophic question a man can put to himself is, Why does anything pass from rest to motion, whether it be in physics, or ethics, or politics?

(2) If we wish for anything like thoroughness in our appreciation of the controversy about efficient causality, we must not shrink from the inquiry into what has been actually maintained on the point by the champions of each side; and if we have anything like a philosophic temper, we shall deem such inquiry interesting rather than wearisome. Our opponents may be divided into two great classes (a) those who fully allow the fact of causality, but think that certainly in regard to matter, and perhaps in regard to mind, God must be the sole cause of the activities; and (b) those who, equivalently abolishing causality, reduce it to mere constancy of sequence. We will take each of the pair separately.

(a) Occasionalism, which we find St. Thomas already in his time opposing,^{12} is the name under which the first doctrine that we have to attack is known. It teaches that created things are the mere occasions on which the Divinity takes the opportunity to act conformably to the requirements of the objects present. This theory is specially characteristic of the school of Descartes, and is in intimate connexion with the reduction of matter by that philosopher to extension, with inertia for its chief property. Matter, according to him, can itself do nothing: it is a mere receptivity and channel of communication or transference for the motion imparted by the Creator: it can hand about movement from particle to particle, but it cannot originate or destroy any; and thus it is opposed to mind, the very essence of which is thought or activity. Matter is inert extension, thought is ever-operative inextension. One short paragraph in the Principia^{13} is a complete exposition of the theory: "We must consider motion in its two causes, the primary and universal cause, to which is due all the motion that is in the world, and the particular cause to which it is due that various portions of matter acquire the movements which before they had not. As to the former, it is evident to me that it must be attributed to God Himself, who in the beginning created matter along with motion and rest, and ever since has preserved these in the same quantity. For, though motion is nothing but a mode in the thing which is moved, yet it is of a definite amount that remains constant for the whole universe, though it varies in regard to the several parts." This constancy the author connects with God's attribute of Immutability. He continues: "Whence it follows that it is most consonant to reason for us to suppose that God always preserves in the world just so much motion as He impressed on it at its first creation." To the soul Descartes allows an activity of its own, but subject to certain qualifications which he fails definitely to express; for he wavers in his view as to the innateness of ideas, and as to the power of intellect to form its own notions on the occurrence of sensible experiences; while he clearly commits himself to the argument that a God must exist, because only as a gift from Him could finite intellect possess its idea of the infinite.

A disciple of the master -- namely, Geulinx, carries his principles to the extreme of rendering both body and soul passive subjects under the Divine hand, denying as well the influence of soul upon body -- which Descartes allowed -- as that of body upon soul. His doctrine in brief is, "Secondary causes have no activity of their own" -- Causae secundae non agunt.

Another Cartesian, somewhat more moderate, is Malebranche,^{14} who quite denies all activity proper to matter, and goes near to making the soul inactive, but saves himself in a sort of mistiness of expression. He fully agrees with his master that all the movement which is to be found in things material is from God, but does not appear to care much for the addition that the sum-total of motion was communicated at the first Creation; while as to the soul he allows it only one mode of immediate intuition -- namely, self-consciousness, all other objects being known to it "through the medium of ideas," which are derived from the intimate presence of God to the mind. It is by his express repudiations that Malebranche saves himself from the charge of some awkward inferences which might be drawn out of his principles in favour of pantheism, and of a direct vision of God in Himself. No doubt he was a pious, well-meaning man, but often not a wise one; and his system cannot be maintained in anything like its substance.

Among our English philosophers many in past, and even in present days, must be ranked with the occasionalists as regards material bodies. Cudworth's remark is good as far as it goes,^{15} "that it seems not so agreeable to Nature, that Nature, as a distinct thing from the Deity, should be quite superseded, or made to signify nothing, God Himself doing all the things immediately." Clarke was openly an occasionalist in respect to matter; Locke sets the question aside as not properly coming in his way, yet describes material impulse as the mere transfer of impressed motion.^{16} Reid and Stewart decidedly tend to occasionalism. The former says:^{17} "Whether the Creator acts immediately in the production of events in the natural world, or by subordinate intelligent agents, or by instruments that are unintelligent -- these I suppose to be mysteries placed beyond the limits of human knowledge. The active power of which alone we can have any distinct conception can be only in beings that have understanding and will. Power to produce any effect implies power not to produce [a confusion between power in general and power of choice]; we can conceive no way in which power may be determined to one of these rather than to another in a Being that has no will." "We are unable to conceive any active power to be exerted without will. The only distinct conception I can form of an active power is that which is an attribute in a Being, by which he can do certain things if he wills. This is, after all, only a relative conception. It is relative to the effect and to the will producing it. Take away these and the conception vanishes. They are the handles by which the mind takes hold of it. When they are removed our hold is gone. If any man, therefore, affirms that a Being may be the efficient cause of an action which that Being can neither conceive nor will, he speaks a language which I do not understand. It seems to me, then, most probable that such things only as have some degree of understanding and will can possess active power; and that inanimate Beings must be wholly passive. Nothing we perceive without us affords us any good ground for ascribing active power to any inanimate Being: and everything we can discover in our own constitution leads us to think that active power cannot be exerted without will and intelligence." The consequence of this opinion, which we often find re-affirmed by English writers, is that though science were to reduce all sensible phenomena to their laws, it would, as Reid himself remarks, only assign the rules according to which some cause works, but it would not prove that cause to be matter itself.^{18} Stewart at first sight seems to go further than Reid, and positively to assert occasionalism in regard to matter; for he affirms,^{19} that "power, force, energy, and causation are all attributes of mind, and can exist in mind only:" but a closer inspection of the context will show that his meaning may be to say, as Reid does, that we know no force but that of will, and that the phrase, "material force," is addressed only to our ignorance, on the strength of an obscure analogy between will and bodily movement. Distinguishing "metaphysical or efficient causes" from "physical," the latter of which means only constancy of antecedent to consequent, he maintains that physical science has to do only with "physical causes," and that "we know nothing of physical events but the laws which regulate their succession." Soon afterwards, if his words are to be taken literally, he distinctly contemplates the possibility of matter being an efficient cause; for speaking of the popular rejection of actio in distans, he says: "That one body may be the efficient cause of the motion of another body placed at a distance from it, I do by no means assert; but only that we have as good reason to believe that this may be possible as to believe that any one natural event is the efficient cause of another." With the examples now given we may suppose the doctrine of occasionalism to have been sufficiently illustrated, so that its meaning and the reasons for it are clearly before the mind.

(b) The next theory to be considered, while retaining the name, virtually abolishes the notion of causality altogether; and Hume is the prime representative of this doctrine. The truth about his theory may be conveyed in three statements: (i.) First, he sometimes argues as though he were going on the supposition of real efficient causality, and labours to prove merely that causality is known to us by its effects alone, while its inmost nature cannot be penetrated by our methods of inquiry. We get no insight into the mode of causality, how it is that agents work, and why their effects are what they are. With this assertion we very largely agree. (ii.) Secondly, he argues that from single experiences of any kind we have no "impression of power," and hence can have no valid "idea" of it from this source; but after frequent experiences of similar sequences, custom produces in us a feeling" or an "impression of power." (iii.) Thirdly, he teaches that this idea of power does not carry us beyond the knowledge of invariable sequence; it does not give us efficient causality; we have no notion of one thing literally acting by its influence upon another. Mill tries to improve on this doctrine, but not with much success; both authors deny causality in its proper sense. The details of their criticism, very important for the right understanding of much modern thought, but too long for the body of this chapter, may be found in the first of the notes at the end of it; they require a little patient reading, but not very deep thought.

(3) The proposition which has now to be proved must be reduced to its most generalized conditions by abstraction from all those connected questions, each of which opens out a field of endless controversy. It can be so detached. We can leave out, for instance, the consideration how created agents act, whether immediately by their substance or through really distinct faculties; and whether any effects from created causes are new substances, or only modifications in pre-existing substances. Again, we can omit the extremely difficult problem of isolating any case so as to get precisely this as cause and that as effect: for every case that we can select, no matter how simple in appearance,, is sure to contain more complexities than we can well unravel. Not to take the simplest example, but to take one which, for the ordinary mind, would seem simple enough, let us suppose a drunkard sleeping out in the field at night, bringing on a very severe attack of pneumonia, and dying. His friends would say variously, and with great assurance, "it was all owing to the drink," "to the cold night air," "to the misfortune of sleep having come on," "to the severity of the inflammation," "to delay in sending for the doctor," "to having summoned Dr. A. instead of Dr. B." The fact is, the process has many steps of successive causes and effects, and to follow them all out in detail baffles human skill.^{20} After having given a few specimens of the particulars which might make our path a thorny one, we return to our declaration that we undertake to show, only in most general terms, that in this world of real changes there must be efficient causes to bring them about, else evolution or development, and decline or retrogression, would give place, if to anything, then to a dead level of perpetual sameness.

(a) We begin with two uncontrovertible assertions, that there are real changes in our universe, and that there must be for these a sufficient reason or cause, wherever that cause may reside. To declare with the Eleatics that change is nothing, is absurd, and it is only an extreme of Hume's^{21} unreasonableness which can account for his words: "We can never demonstrate the necessity of a cause to every new existence, or new modification of existence, without showing at the same time the impossibility there is that anything can ever begin to exist without some productive principle. Now, that the latter proposition is utterly incapable of a demonstrative proof, we may satisfy ourselves by considering that all distinct ideas are separable from each other, and as the ideas of cause and effect are evidently distinct, it will be easy for us to consider any object to be non-existent this moment and exist the next, without conjoining to it the distinct idea of a cause or productive principle. The separation, therefore, of the idea of a cause from that of a beginning is plainly possible for the imagination, and consequently the actual separation of these objects is so far possible, that it implies no contradiction or absurdity."^{22} For it is a principle which Hume adopts, that what is conceivable is possible.

To those who instead of a mechanical association of units, called ideas, believe in man's power of rational insight into objective truth, it is clear that the only sufficient account of real change is what we designate by the term "efficient causality." Whatever before was not, and now begins to be, owes its being to something other than itself. The otherness may not be complete, but at least it is partial, for even an immanent agent under the aspect of its power to produce an effect is distinguished from the same agent under the aspect of its receptivity of that effect in itself a subject, and from the effect received. No real act is without real effect, though the effect be identical with the act. All science depends on holding these principles, and not only all science in the grander meaning of the word, but likewise in the meaning of all genuine knowledge.

The dynamic aspect of the world is, therefore, as real as the static; the universe presents problems of kinetics as well as kinematics. We must admit something which is as truly an agent as it is a Being, which acts as truly as it is. Where this agency is we leave an open question for the present; but a real agency we prove to exist.

In support of the universal recognition of efficient causes Reid appeals to the unmistakeable tokens of conviction among mankind.^{23} "The arguments which I have adduced," he says, "are taken from these five topics: That there are many things which we can affirm and deny concerning power with understanding: That there are in all languages words signifying not only power, but signifying among other things that empty power, such as action and passion, cause and effect, energy, operation, and others: That in the structure of all tongues there is an active and a passive form in verbs, and a different construction adapted to these forms, of which diversity no account can be given but that it has been intended to distinguish action from passion: That there are many operations of the human mind familiar to every man come to the use of reason, and necessary in the ordinary conduct of life, which imply some degree of power in ourselves and in others: That the desire of power is one of the strongest passions of human nature." One always regrets that Reid, who says so much which is good about the real power of created will, should also have said so much against any real power proper to material things, and should have lamented that^{24} "even the great Bacon seems to have thought that there is a latens processus, as he calls it, by which natural causes really produce their effects."

The argument for the bare fact of efficient causality must be completed by the settlement of a question which arises as to the immediacy of the perception in regard to the abstract principle. The inquiry is, whether the general principle, that every new reality must have a cause, is immediately evident, or whether it is, as Mill contends, an induction from experience. To save himself from the vicious circle of grounding Induction on the principle of Causality and the principle of Causality on Induction, Mill^{25} distinguishes a natural knowledge of the principle which precedes the inductive proof, from the scientific knowledge which is the outcome of that proof. In behalf of the need of an induction, Mill argues from the fact of the very tardy acquiescence of mankind in the reign of law, or in the belief that things do not happen at hazard, but all according to definite causation. We reply that rude peoples are not so much astray about the abstract principle, that whatever happens must have a cause, as about its application. They see so much happen for which they cannot account, and they are so accustomed to the freaks of their own free-will, that they overlook the need of an account to be rendered for every event, or they find that account in a cause called Fate, which is the impersonation of the freakish Will. But whatever may be the explanation of the blunders of the incompetent, when we rationally consider the principle of causality, we have a right to pronounce it immediately evident, or if we like to resolve it into elements, we may.^{26} It contains the propositions: Every thing must have a sufficient reason why it is rather than is not, and why it is thus rather than otherwise: The only sufficient reason for a real change is efficient causality: Therefore every real change has an efficient cause. So worded the principle escapes the charge of tautology, to which it is liable as long as it stands in this shape, "Every effect must have a cause."

(b) So far we may claim to have established that we do find efficient causality at work in the world; the next point we have to prove is, that this causality is not simply Divine, but that creatures act. We will begin the inquiry by another question about immediacy, Have we any immediate perception of created causality itself, or is it all at best a matter of inference? The answer depends largely on our way of talking, and is akin to the difficulty found by logicians in discriminating what they call immediate inferences from inferences in strict syllogistic form. At least it may be affirmed that man has immediate consciousness of his own activity, as that of which he is the cause, in some of the acts of the will. If it is objected that consciousness testifies to facts, but not to what philosophers often call the how of facts, we deny the assertion to be universally true, otherwise we should not know some acts to be pleasant, others unpleasant, some to be according to our will, others against it. When it is said that such truths as the spirituality, the immortality, the substantiality of the soul are matters not of direct consciousness, but of inference therefrom, there can be no intention to place every piece of information about the thinking principle in the position of an inference: at least some characters are immediately revealed. Notably our own causal activity is a fact of which we are directly aware; and if we single out the act of free choice especially, it is not that we wish to exclude all other acts from the list of these which give immediate testimony to our causality; but we fix upon the most prominent of our own free acts as pre-eminently establishing the point in question. Nor do we think it any objection to the immediacy of the testimony, that it needs some reflective thought explicitly to recognize what causality is, how it differs from mere sequence, what it is to be the principle whence causality flows; and so forth. Even the three primary principles about Being and Not-Being need reflexion explicitly to formulate them, and, as we were made painfully to perceive in the chapter on Being, the primitive notions can be described only by the employment of great care. Under fair allowances for immediacy we have some immediate knowledge of causal activity as a fact in the concrete.

(c) Having found at least one case of efficient causality in created agents, we have now to prove it for other cases. Anticipating results, we may divide man's experienced proof of efficient causality into a succession of certainties, all deserving their name, but varying in rank. (i.) His highest certainty is about the activity of his own intellect and will. Coleridgians insist mainly on the latter, and say that only by the consciousness of an originative will within us can we be secure against Hume. (ii.) Man's certainty next in degree, is that he exercises some causality in movements of his own body -- in some if not in others; and this truth holds in spite of Reid's assertion,^{27} "For anything I know to the contrary, some other Being may move my hand as often as I will to move it." (iii.) Man is sure that other bodies act on his, and also (iv.) that they act inter se, one on another, though knowledge of the fact depends on their action upon his own body.

All our task will be accomplished if we can give valid reason for holding that material substances are real agents. We may begin with a difficulty that applies equally to acts of our own will, though we did not mention it when speaking on that subject: for its plausibility is greater with regard to the agency of external bodies, about which we are now to treat. Suarez, in defence of his peculiar theory that action is modally distinct from its own intrinsic term, or that the product of the action has the action itself for its really distinct mode, allows that God might absolutely bring about these acts without the concurrence of the faculties in which they inhere.^{28} "God might Himself alone produce these acts, so far as they are certain qualities, without the active concurrence of the faculties, whether He produced them as forms inherent in the faculties, or not; for this latter point is quite another inquiry. Hence it is not of their essence that these qualities should depend on the faculties." Having allowed that this opinion has the support of so respectable an authority as Suarez, we deny its force against the doctrine we here maintain. For to pass over what we have already shown, that whatever might have been, yet de facto consciousness testifies the origin of our thoughts and volitions to be from our own causal agency, and testifies against the mere infusion of them into our passive soul; we single out especially the effects that take place in material bodies, and observe that at best the theory of Suarez would go to show that by miracle God might work the results which we call natural. Now we do not dispute that God might, by His sole power supply much of the causal influence which brings about physical changes in matter; but that He commonly does so is a supposition derogatory to the Divine attributes. We are at least half- way on to pantheism if we make all material action Divine; furthermore, as we know things only by their activities, there is no reason why we should assert those inert masses if we suppose them to be nothing but idle occasions of the Divine operations. As Berkeley says, "Nobody will miss them," so let them go. Leibnitz and many others declare that the very notion of a Being with no activity native to it is a contradiction, and that there can be no actus primus without an actus secundus. At any rate God's works have a perfection of their own which marks them as worthy of their Maker; hence the maxims:^{29} Natura non deficit in necessariis -- "Nature fails in no requisite;" and ouden matên -- "Nothing is without a purpose," as matter would be, if it were so absolutely inert as to be in a condition of simple do-nothingness. It may be said that these maxims are theological. This is not exclusively true, for they have a foundation on the generalizations of experience; but they are also theological, and under this aspect they just meet present exigences. For the occasionalists against whom we are contending appealed precisely to God in their theory that the efficiency, which we want to prove to be in nature, was not from nature, but from its Author: and it is on considerations which concern the requirements of Divine wisdom that we frame our reply.

We give the argument from St. Thomas: "If effects are not produced by the activity of creatures, then they cannot manifest to us the powers of creatures; for it is only by means of the activity which, coming forth from the cause, finds lodgment in the effect, that the effect can show us what the power of the cause is. Now the nature of an agent is known from its effects, only so far as its power is thereby known; the power being in accordance with the nature. If, therefore, creatures exert no activities that produce effects, it follows that never could the nature of a creature be known by its effects: thus we lose all natural science, which proceeds chiefly by the method of demonstrating causes from their effects."^{30}

The proof admits of a further development on these lines: it is a matter of our inmost conscious experience that our own bodies act: therefore matter has certain inherent activities; therefore it is reasonable to assert the activity also of lifeless matter. If in the living body matter is not the mere passive recipient of the soul's causality, but has a causality due to itself, then the theory that matter is essentially inert, in the sense of wholly inactive, falls to the ground.

Here then we end our argument for the broad fact of natural causality: but we must repeat that it is only the broad fact for which we have been contending, not for the mode of operation. Mr. S. Hodgson must be trusting most deceptive guides when he affirms, in the teeth of plain facts, that "the schoolmen assumed the general conception of causal energy as equivalent to a knowledge of what causal energy consists in;" and that Hume made a strong point against them when he showed we have no knowledge of what is the nature of force. The schoolmen were well aware of the distinction between the that and the how, and did not stake the fate of the first inquiry on the success of the second. Rather it was those who were bent on penetrating the how who fell away from the common-sense view. To account for his defection, Malebranche says:^{31} "The chief reason is the inconceivability of the thing: try as I may, I cannot find a representation in my mind of what this power is which is commonly attributed to creatures." Hume also insists much on the same inconceivability to justify his scepticism. The difficulty is admitted, but fortunately it need not be encountered, else we should be in a hopeless state, for it has puzzled the most penetrating genius. Laplace declared that "the nature of force is and ever will be a mystery." But he did not on that account deny force, or renounce all knowledge of its nature: he held that we can determine "its actions and its effects." The mystery of essence and the mystery of the substratum, were the stalking-horses behind which adversaries attacked essence and substance; and under the same shelter of mystery they attack causality. We allow a mystery, but likewise contend for something plain to the ordinary intelligence. We are not to be driven from this plain truth by the cry of mystery. Hence we are struck more by the incompetence than by the argumentative skill of a man who will tell us, like Mill,^{32} "that the notion of causation is deemed by the school of Metaphysics most in vogue at the present moment, to imply a mysterious and most powerful tie, such as cannot, or at least, does not exist, between any physical fact and that other physical fact on which it is invariably consequent, and which is properly termed its cause; and that thence is deduced the supposed necessity of ascending higher into the essences and inherent constitution of things, to find the true cause, the cause which is not only followed by, but actually produces the effect." Unmistakeably in our intellectual ascent we can go as high as "the cause which certainly produces the effect:" but we do not pretend to have risen to that upper region of the mysterious; we content ourselves with what we can claim to be securely sure of, namely, real efficiency. Kant is another opponent of the reality of our notion about causality; but as this is not the place to open out the whole question of his a priori categories, we must content ourselves with the assertion that what he regards as a mental form, we have proved to be the idea of a reality. We have shown that there are real causes effecting real changes among things in themselves. Even Kant has confessed as much. For, greatly to the disconcertment of his friends, he argued that we know the existence of noumena, or of things in themselves, because they are the efficient causes of impressions upon our organs. No special pleading has been able to conceal this inconsistency in Kant's theory. Whereas he ought to have regarded the category of causality as not valid beyond subjective phenomena, he has unguardedly applied it to things in themselves, as though they were knowable as real causes. He was right in so arguing, but the argument implies the renunciation of his theory about the categories. And as we are on the subject of differences of meaning in the use of terms, it may prevent useless cavils if we add, that in defending the reality of created force, spiritual and material, we take the word on our own interpretation of it, not in any or all of the interpretations which various authors have given. Hence many an adversary will be saved a deal of misdirected efforts, if he puts aside his own notion of what force ought to mean, and investi gates whether our sense is not vindicated by our arguments.

(4) While we do not pretend to clear up many of the obscurities which beset the question of causality, at least we may give explanations of some current phrases, and so dispel certain mists that unnecessarily are allowed to confuse the view.

(a) "The effect is like its cause." How, then, have the same philosophers who adopt this principle, divided causes into univocal and equivocal, the univocal being those in which like produces like, as when living things produce their offspring, and the equivocal being the opposite to univocal? The whole account seems preposterous, and has proved a scandal to more than one weak brother in the philosophic fraternity. If an artist carves the figure of some animal whose name is a reproach when applied to man, are we justified in quoting to him the maxim, "The effect must be like its cause"? All the difficulty arises from taking cause and effect in the rough, instead of in their proper analysis. What we ought to look to is the precise causality --that and nothing more -- which the artist has exercised. We find that he did not produce his own materials, nor did he expend upon them every variety of his causal powers, still less his whole self; yet he did exert upon them a certain causality, or rather a countless succession of causalities, which are identified with his total effect upon the materials, and therefore it would be strange indeed if this causality were not like the effect. Though the causality may not always be such as to indicate the full nature of the agent, it must always be in conformity to that nature: no agent can effect anything quite out of character with himself or itself. This is the substantial meaning of the principle we are explaining, and the meaning evidently conveys a truth in flat contradiction to Hume's error. He said that for aught we can determine a priori, anything may produce anything, and events may succeed quite at random.^{33} "As all objects which are not contrary are susceptible of a contrary conjunction, and as no real objects are contrary [the only contraries with Hume being existence and non-existence], I have inferred from these principles, that to consider the matter a priori, anything may produce anything, and that we shall never discover the reason why any object may or may not be the cause of any other, however great or however little the resemblance may be betwixt them. This evidently destroys the reasoning concerning the cause of thought or perception. For though there appears no manner of connexion betwixt motion and thought, the case is the same with all other causes and effects." A man to whom causality is mere succession of ideas without reasonable objectivity and without any efficiency, may easily acquiesce in the conclusion that anything may be the cause of, that is, be constantly followed by, anything. Still, if Hume can show that there are "no real opposites," he will have gained a decided point in his favour: and, moreover, he may seem to be able to claim some support from us, who have laid down such doctrines as that evil is not a thing, that impossibility is nonentity, and that all Being is true. Now, if these teachings are correct, and especially if Being is essentially true, the proposition that truth cannot contradict truth may be turned into Being cannot contradict Being. The inference is that there are no real opposites, and that the only opposition is, as Hume says, between existence and non-existence: hence no real opposition between any cause and any effect, and so far at least "anything may produce anything." In reply, let us recall what our doctrine has been. We have taught not that nothing evil is real, but that the evil qua evil, might be reduced to the idea of a privation. An illustration used was that a cancer is a real evil to man's body, but that yet the cancerous growth in itself, as an existence, is not evil; its progress is all very well for the cancer. The evil springs from the relationship; man and cancer have not got sufficient powers to enter upon terms of mutual accommodation, and the good fortune of the cancer results in deprivation to man. Two finite perfections may be such as to be essentially opposed, and mutually exclusive; but the opposition comes of the finiteness of one or other, or both, not of their perfection as such. Similarly, our explanation of impossible combinations between finite Beings, each of which was true in itself, left ample room for contradiction, and positive contradiction, in falsely asserted conjunctions. When then we, against Hume, maintain that between certain causes and certain effects, the opposition may be such as to warrant the argument a priori that certain causes cannot have certain effects, we speak of an opposition between realities. Such opposition we may call real, however true it may be that opposition implies contradiction, and a contradiction is a nonentity, or the intrinsic impossibility of actualization. So far as no cause can give what it has not got, by producing something wholly opposed to its nature, which furnishes the law of its activity, we are right in the statement that effects must resemble their causes to the extent in which these causes are productive of the effects; but we must be careful to note, if we can, what precisely is this extent.

To sum up results: nothing gives what it has not got: nothing can act in a way quite unlike its own nature: therefore every activity must have a certain likeness to the agent. Now the effect, so far as it is the effect of this particular agent, is only that agent's activity as received into some subject: in this sense, and not in some mysterious sense which no one can exactly make out, every effect is like its cause. The likeness must be recognized simply in the way we have pointed out, not by trying to make a drawing of it, in any other manner that is unavailing. The case is analogous to the likeness of knowledge to its object; consider what true knowledge must mean, and then observe that likeness expresses the relation; do not try to paint the likeness.

(b) "The cause is prior to its effect" -- Prius est esse quam agere. To the bucolic intelligence the statement wouki seem obvious, and the agricultural labourer would quote in proof of it his spades, hoes, scythes, and ploughs, which have to be made before they can be used. The whole substantial thing exists at least before many of its acts; still it has other acts not usually taken into account, which in point of time are as early as the substance. As far as we can see, a newly created piece of matter would be created gravitating; and, indeed, if we look at action, not as the production of new "forms," but as attraction and repulsion, it seems questionable whether the elements ever do anything else than act with one equal intensity from beginning to end, all difference in effects being due to differences in the balance of opposing forces, and in their respective distances. We are told that a weight on a table, though it does no work, gravitates all the time, and must have its downward tendency checked by an antagonist pressure upwards. We are almost quite in the dark as to the mode of action; but it is a wholesome reminder to be told not to be too free in speaking of causes issuing from potency into act, or of an effect being in fieri and in facto esse, in process of production and a product. What is taken as the first issuing forth of activity may be only the first release of that activity into open manifestation, and what is taken as the process of one effect is often the succession of many different effects. Here once more the case is presented in which we must be on our guard against taking a series of causations for one simple causation. If the fire is considered as the cause, and the condition of being cooked as the effect, then it looks as though the effect on a round of beef was a long time in coming -- quite an illustration of the difference between in fieri and in facto esse. But if we examine the process more accurately, each factor of the causation is found to be synchronous with each factor of the effect. Hence the maxim, Causa in actu et effectus in actu sunt simul. It is not, then, in the order of time, but in the order of nature that the cause, acting qua cause, must be prior to its effect. Not that with Lewes we may make the effect the mere sum-total of the causal agents: for besides the agents there must be their agencies, real issuings forth of activity, and it is the sum-total of these that may be identified with the effect. The cook who makes a pie efficienter, as efficient cause, does not make it constitutive, as constituent cause, or we should often be cannibals at dinner. The cook is not identified with the cooked materials or with any part of them, but the cook's agency -- which is only a portion of the whole agency required -- is identified with her effect upon the materials. She really does produce an effect, and "in the order of nature" the producer is always prior to the producing, though in time producer and its production may occasionally have a simultaneous origin. Herein our doctrine differs from that of Lewes, who says,^{34} "Cause means unconditional antecedence. The metaphysical conception of a cause, the producer of an effect, needs limitation. We can know nothing of the final nexus. When we say heat produces expansion, we simply express the observed facts that one heated body brought near a colder body begins to contract, and the other simultaneously begins to expand; nothing new has been produced, a mutual change in the condition of the two bodies has resulted in the transference of so much motion (heat, expansion) from one body to another." To effect even a transference is some sort of real production; but what we should give special attention to is, that on Lewes's showing, "invariable antecedence" is declared not to be antecedence; or causality is reduced to antecedence, on the understanding that the antecedence need not be antecedent. For if cause and effect are simultaneous, one is not before the other; there is no precedence where the conditioned is simply the sum of the conditions. Hence Lewes himself adds, "Rigorously speaking, we must limit even the expression of necessary sequence, which is held to express all that is known of causation. There is no following of effects from causes; but, as Sir John Herschel more truly says, the causes and the effects are simultaneous. . . . We say that the earth's attraction causes the weight of the apple; but the weight is the attraction, they are two aspects of one unknown reality." This is awkward in the mouth of Lewes; but we can easily accommodate ourselves to circumstances. We say that inasmuch as action is productively exercised by a substance which is the causal agent, the cause is prior, at least "in the order of nature," to the effect; but the causality is contemporaneous with its effect -- not necessarily with the whole result which is roughly denominated effect -- for the two are the same thing under different aspects. Thus we at any rate are free from certain grave difficulties which beset the empiricist, for whom causality ought always to mean antecedence in time.

(c) "The same cause, under the same circumstances, always has the same effect." An ambiguity here lies in the word "circumstances." As before, we found "attribute" taking the place of its opposite, "essence" or "substance," so that we got "essential" or "substantial attributes," and as we found "accidents" having their own inferior kind of "essences," so that we could speak of the essence of some accidental property being so and so; similarly now, "circumstance " comes to usurp the whole field to itself. At last we ask in bewilderment, "Where is that round which something else stands?" Now, if we take man's free choice as this central point, then it forms an exception to the rule, "The same cause, under the same circumstances, always has the same effect," provided we further understand cause as "agent," and not as "agency," as that which acts, and not as one definite mode of its activity. But apart from liberty of choice in all other causes the rule holds both of agent and of agency. It is true that exposure to what we may suppose the same climate is said to give different men different diseases, and other men no disease at all; but even if we allowed the exposure to be exactly the same for all, yet the men exposed differ vastly one from another. Hence if generically "man" and "climate" are the constants, in the concrete we have not the same "circumstances." In what is called the "plurality of causes" -- or the doctrine that one effect may be due to a variety of causes, we must distinguish two things -- its bearing on practical science and its bearing on philosophic analysis of what precisely causality is. On practical science the result may often be very prohibitive, because, at least so far as we can detect, a given effect may be due to any one of a multitude of causes. The obstacle is real, though its reality may be exaggerated.^{35} Next, in abstract philosophy, the case is still a difficulty. An angel, a human arm, or an explosive mixture may each give the same rate of velocity to a missile: if we identify the causality with the effect, so far it looks as though in each cause the causality was the same, though certainly the three causes were very different. The more we go into the details, into the several modes of producing motion, into the difference between agent as acting, action, and effect, the more we find opportunity for raising questions. And yet, after all, we may defend our original statement as true. For whatever may be the correct doctrine about the "plurality of causes,"^{36} that is a matter which affects only the tracing back of special results to special causes; it is an empirical process, an investigation a posteriori. Whereas our proposition is general, its procedure is in the reverse direction, from causes to effects; its truth is a priori. We affirm that given a necessary cause which has fixed laws of action, then if that cause exerts itself under conditions that are just alike, its own precise effect will be just alike. Otherwise we should have indeterminism in Physics, and contradiction in Metaphysics. It is raising quite an irrelevant issue to remark, that never, in the whole history of the cosmos, are exactly the like circumstances repeated; they approximate near enough to identity for all practical purposes.

(d) "On the cessation of the cause the effect sometimes ceases, sometimes not." When Keats desired to have as his epitaph, "Here lies one whose name is writ in water," he evidently distinguished the effect which perishes at once from that which endures. What is it that makes the difference? In the world of mind, according to some, there are no passing effects, but all are permanently stored up in memory; such at least is a theory which Hamilton adopts.^{37} But if we take the world of matter, then probably our best guides are the laws of motion, according to which no effect ceases, except when it meets with some counteracting cause whereby it suffers transmutation. By the force of gravitation waters just divided close up again; the wind obliterates traces on the sand; the London atmosphere eats away carvings on stone; and the whole question of endurance appears as one of the absence of opposing forces. We are not justified in saying positively that local movement is the only effect producible by matter; even in those sciences which are mathematically reducible to modes of motion, these modes need not be the whole effect; still the laws of motion seem to give us the best criterion we can find for judging about the nature of permanency in material effects. A German philosopher, Herbart, has largely used the analogy of impact between material particles to illustrate the process by which ideas are checked by ideas; but it is only an analogy and is overworked.

On the whole we must admit that the saying, "On the cessation of the cause, the effect ceases," is only as a piece of popular philosophy, and that it needs to be explained, and even explained away.

The axioms about causality so far discussed are typical instances; and what we have laid down in their regard will serve for the elucidation of others, such as that the "effect cannot excel its cause." Throughout, the principles on which we must fall back are especially two given by St. Thomas, that between the agent and the patient there must be some sort of difference, and that yet action and passion are one thing under different relations. "The thing under the same aspect cannot be both in act and in potency:" "When something effects an alteration in itself, it is not agent and patient, mover and moved under the same aspect;"^{38} "Action and passion are the same entity, and differ only according to their different relations."^{39} So teaches St. Thomas, though because of other passages,^{40} his meaning is not undisputed. In the utterance last quoted, which contains a principle to which we have often recurred, he is but repeating doctrine to be found in Aristotle, who said^{41} that "action and passion and motion are the same thing" -- prôton men hôs tou autou ontos tou paschein kai tou kineisthai kai tou energein legômen. Mr. Wallace^{42} thus translates the whole passage: "Let us in the first place agree to regard in our discussion the words passive impression, movement, and activity as identical: for movement is a species of realized activity, though it is imperfect. Now in every instance things are impressed and set in movement by something which is capable of producing an impression, and which exists in full activity. And thus an impression is in one sense made by the like, in another sense by the unlike; for it is as unlike that anything suffers an impression; after the impression has been made, it is converted into like." In this sense it is said that while the effect must be like its cause, the agent, as such, must be unlike the patient, as such; and yet the agent must have a nature conformable or like to its own activities.

(e) "A cause is more than a condition." This saying is of a different type from those previously explained, and leads some people to a hazy and erroneous idea, that a condition may positively do something, without being a cause. We must try to distinguish different senses.

The most pure instance of a condition is one which does nothing, but consists in the mere absence of an obstacle. Thus a window is a condition of seeing, because it does not impede the course of light; it may be a simple hole, as in more primitive buildings, or it may be glass, inasmuch as it has the negative quality of not appreciably obstructing the luminiferous waves. But the best glass gives no light of its own, as we may verify for ourselves at night, when the candles are out.

The second case of a "condition," is one where the reality does something positive, but, as a cause, it is so comparatively inferior in rank, or so far removed from the final result as not to be reckoned among the causes. This is instanced by the oft-quoted relation of the bellows-blower to the organist. The former has positively to cause something, but his work is unskilled labour, and he is not the immediate producer of the musical sound. If we were so inclined we might also call the organist a condition; for he only opens the vents and lets the imprisoned air act on the tubes; but because it requires much skill to press the keys in the ways required, the actions are dignified with the title of principal causes. The remoteness of the organ-builders, or of the musical composer from the actual playing at the time, would lower them to "conditions," though in point of dignity they might claim to be causes.

A third meaning of "condition" refers to a moral agent, who is not simply made to act upon the fulfilment of certain "conditions," but chooses to act where these motives are presented. Thus, the grace of God is sometimes "conditioned" by certain acts on the part of man, though there is no obligation, not even one consequent on a promise given. If not the free acts only, at least the free acts especially, of a moral agent deserve to be styled acts dependent on conditions.

We conclude that in reference to a moral agent, so far as his action is distinctively moral, a condition furnishes a requirement without which he will not act: while in reference to physical agency as such, a condition is either a remote or a comparatively insignificant cause, or else it is the absence of a possible obstacle.

An occasion is a conjunction of causes, efficient and material. Those who speak of the evolution of our solar systems from a primitive nebula, have noticed that, not only the primitive elements of matter in such a nebula need to be accounted for, but that likewise their collocation, their arrangement, their distribution, is a distinct fact about them, of which some account should be rendered. Now an occasion answers to this collocation: it always must have a distinct cause, but in itself we regard it as an incident of causation, not as a cause. If on the occasion when a flower is ready to scatter its seeds a high wind arises, they are dispersed all the further; if on the occasion when a tile falls from a roof a man is passing just under the spot where it falls, he is injured. Our ordinary practice is, to take the conjunction of two or more causes which we regard as practically independent, to ignore the cause or causes which have brought them into conjunction, and then, to speak of their combination as occasional. In the example of a free agent, he may choose his occasions because of their special fitness to his purpose, and they may become conditions of his action.

We forbear further illustration of the maxims of causality. We fail indeed to explain some of the points which they suggest because our knowledge of the mode of causality is very limited; nevertheless, we are able to sustain our main proposition, which is, that we can make sure of real causes in the created universe.

NOTES AND ILLUSTRATIONS.

(1) The promised account of the three doctrines about causality which are to be found in Hume, must now be given.

(i.) In proof of the first of the three assertions, that often Hume only argues that our knowledge of causes is a posteriori, not a priori, it is enough to refer to the Essays, sect. vii. Part I. Here it will be seen that he is working out his principle, that "when we know a power we know the very circumstance in the cause by which it is enabled to produce the effect; so that from such knowledge we should be able to predict, apart from experience, all that the power is able to effect." His arguments tend not to disprove real causality, but merely to show that while we are made aware of much real activity, yet we never penetrate into the secrets of its nature. For lack of the perfect knowledge of power in its inmost character, he renounces his claim even to the imperfect knowledge, which, nevertheless, he perpetually supposes. He says, for example, of our inner experiences, that "if by consciousness we perceived any tower or energy, we must know this power; we must know the secret union of soul and body, and the nature of both these substances." The assumption is more than a trifle extravagant, that unless a man knows all about power he knows no power at all. It is the old story of the "hidden essence" and the "hidden substratum," which we considered when treating of essence and substance; nothing is known because something is hidden.

(ii.) Our second statement about Hume, that the "impression" of force or power is given by no single experience, but only by repeated experiences, is proved by citation from Part II. of the same Essay, which may be copied out with little comment; it contains the pith of his whole theory, and should be carefully read: "We have sought in vain for any idea of power, or necessary connexion, in all the sources from which we could suppose it to be derived. It appears that in single instances of the operation of bodies, we never can, by our utmost scrutiny, discover anything but one event following another; without being able to comprehend any force or power, by which the cause operates; or any connexion between it and its supposed effect. The same difficulty occurs in contemplating [singly] the operations of mind on body, where we observe the motion of the latter to follow on the volition of the former, but are not able to observe nor conceive the tie which binds together the motion and the volition. The authority of the will over its own faculties and ideas is not one whit more comprehensible." After examining the operations of outer body upon outer body, of will upon our own body, and of will upon the mind's own actions, he pronounces that, "on the whole, there appears not any one instance of connexion which is conceivable by us." So he repeats the old blunder of confounding together the knowledge of a fact, and the knowledge of its inmost nature; because he cannot conceive the how (dioti) of the connexion, he cannot affirm the that (hoti) -- that there is a connexion. Hence he continues, "All events seem entirely loose and separate; one event follows upon another, but we never can observe any tie between them." Then he draws his conclusion, that from single experiences there is no "impression of power," and consequently no "idea." What he fails to find in single instances, he next proceeds to seek and find in the repetition of many similar instances. From neglect of this part of the theory, some report Hume as wholly denying that we have the impression of power from any source. Whereas his words are clear: "There is nothing in a number of instances different from every single instance, which is supposed to be exactly similar, except only that after the repetition of similar instances the mind is carried by habit, upon appearance of one event, to expect its usual attendant, and to believe that it will exist. This connexion, therefore, which we feel in the mind, or customary transition of the imagination from one object to its usual attendant, is the sentiment or impression from which we form the idea of power or necessary connexion."

(iii.) The third point that remains to be shown is the manner in which Hume arrives at no objective knowledge of causality, strictly so called, but only at invariable sequence, and that in the subjective order of feelings. The passages in support of this interpretation are embarrassingly numerous. Let us begin with the following:^{43} "Reason can never show us the connexion of one object with another, though aided by experience and observations of their constant conjunction in all past instances." Therefore, whatever be the way in which Hume arrives at causal connexion, it is not by the way of reason; and that is an important declaration, though afterwards what it says is unsaid. "When the mind passes from the idea or impression of one object to the idea or belief of another, it is not determined by reason, but by certain principles which associate together the ideas of these objects, and unite them in the imagination. Had ideas no more union in the fancy than objects have in the understanding, we could never draw any inferences from causes to effects, nor repose belief in any matter of fact. The inference, therefore, depends solely on the union of ideas." In strict logic, he assures us, each new revision of our judgments should go on diminishing their probability, which was all they had to start with, till at last every vestige of probability is lost. Logically this should be; but nature is too strong for Logic, and the only good we get out of considering what Logic has to object against our way of procedure is, that it "makes the reader more sensible that all our reasonings concerning causes and effects are derived from nothing but custom; and that belief is more properly an act of the sensitive than of the cogitative part of our nature." For the result of reflexion being such that it gradually "reduces the original evidence to nothing," the inference is that^{44} "if belief were only a simple act of thought, without any peculiar manner of conception or addition of force and vivacity, it must infallibly destroy itself." Nevertheless, since each one, "though he can find no error in the foregoing arguments, yet continues to believe as usual, he may safely conclude that reasoning^{45} and belief is some sensation or peculiar manner of conception, which 'tis impossible for mere ideas and refiexions to destroy." Thus the reason which Hume sets over against mere modes of sensation or feeling, in the end is reduced to a mode of feeling; and the principle of causality, which reason cannot prove, is declared to be reasonable, because reason after all is not reason, but a kind of sentiment which is natural to us, and which it is useless logically to dispute, though logical disputation, if employed, is fatal to its claims. We know causality by a process which both is not reasonable and is reasonable: it is not reasonable, because reason is logical, and Logic pronounces against causality; it is reasonable, because reason is a kind of feeling, and we have a "feeling" of causality. If these exhibitions of fatuity should do anything towards making apparent the chaos of confusion into which Hume precipitates himself, the effect on the appreciation of much modern philosophy will be highly useful; for this last is not radically better than that of Hume which it aims at slightly improving.

It is well that we should thus be brought across Hume's wavering tendency between making knowledge a matter of "natural propensity," and distinguishing "natural propensity" from knowledge. He says,^{46} "After the most accurate of all my reasonings, I can give no reason why I should assent to it; and feel nothing but a strong propensity to consider objects strongly under that view under which they appear to me." And his final decision, given almost at the end of the First Book, takes this shape: "Where reason is lively and mixes itself up with some propensity it ought to be assented to; where it does not, it can never have any title to operate upon us." If some should think that this is only a clumsy expression of the truth, that ultimately we must believe because of felt conviction, they have only to consider the application to our present subject of causality, and they will see how Hume makes it the very triumph of his system, that it holds equally for the animals below man and for man himself. Once more our vouchers shall be Hume's own words. He has to explain the necessity of connexion, which forms part of our notion of causation; and here is his explanation:^{47} "The idea of necessity must be derived from some internal impression. There is no internal impression which has relation to the present business, but that propensity which custom produces to pass from one object to the idea of its usual attendant. This, therefore, is the essence of necessity. Upon the whole, necessity is something which exists in the mind, not in objects;^{48} nor is it possible for us ever to form the most distant idea of it, considered as a quality in bodies. Either we have no idea of necessity, or necessity is the determination of the thought to pass from causes to effects, and from effects to causes, according to their experienced union." Then he adds^{49} as "an invincible proof" of his system of explanation, that it applies to the knowledge both of man and beast. He is aware that this theory is of all his paradoxes^{50} "the most violent," and very much against "the inveterate prejudices of mankind;" yet he makes bold to maintain it notwithstanding. In regard to causality, he asks us to believe, on the one side, that as far as reason can see, "anything may produce anything; creation, annihilation, motion, reason, volition" -- all these may arise from one another, or from any other object we can imagine, on the other side "we infer a cause immediately from its effect, and this inference is not only a true species of reasoning, but more convincing than when we interpose another term to connect the two."^{51} Evidently Hume has two sorts of reason, and the marvel about them is, that one of them is irrational yet valid, while the other is rational yet invalid.

Of Hume's recent followers we will take only one, Mill, who felt that his leader's definition of cause was inadequate. The definition stood: "The cause is an object followed by another, and where all the objects similar to the first are followed by objects similar to the second;" or "a cause is an object followed by another, and whose appearance always conveys the thought of that other." Mill saw that this clumsy formula, so far as it provided for anything, provided only for invariable sequence, and invariable sequence need not be causality; hence he added the word "unconditional," and said that causality was "invariable and unconditional sequence."^{52} Day may have invariably followed upon night, without thereby proving itself the effect of the latter, for it is conditioned "on the existence of the sun or some such luminous body, and on there being no opaque medium between that body and the part of the earth where we are situated; these are the sole conditions, and the union of these, without any superfluous (?)^{53} circumstance, constitutes the cause." All the advance which Mill here makes upon Hume, is that he secures attention to a completer enumeration of the several parts of the antecedent; but having provided for this completer enumeration, he leaves causality in the category of mere invariable sequence, without any productive power. He has pointed^{54} out with a great deal of good sense, that what we generally call "the cause," is only a part of it, and he adds that, adequately taken, "the cause is the sum-total of the conditions, positive and negative, taken together; the whole of the contingencies of every description, which being realized, the consequent invariably follows." The practical difficulty is to know where to stop in the attempt at such an exhaustive method of enumeration; for it would carry us back to the beginning of the world; and the fact that we must break off a long way short of this initial point has formed one link in the argument of some who assert that our propositions about nature, because we can never perfectly isolate one truth from its connexions, must be hypothetical, not categorical. In his own writings, and in the very place we are discussing, Mill exemplifies the incompleteness which he is condemning. For he is satisfied with the presence of a luminous body and the absence of an opaque medium, as constituting the conditions of day; whereas there is further need of a transmissive medium, such as the luminiferous ether. Again, so long as he assigns no exact meaning to the word "day," it is impossible to decide whether, even apart from the omission of the ether, he is right in calling a luminous body, and the absence of an opaque medium between it and the earth, rather "the cause of day," than day itself. Some people call it "day," even though a solar eclipse should be going on between sunrise and sunset; and in that case one of Mill's "invariable antecedents" to the undefined consequent "day," has taken the liberty to vary. In a later chapter of the same book (c. xix. § 1), Mill gives his account of day in other words: "Day is not the cause of night: both are successive effects of a common cause, the periodical passage of the spectator into and out of the earth's shadow consequent on the earth's rotation and on the illuminating property of the sun."

But our main objection to Mill is that he denies our knowledge of efficient causality, without which his "invariable and unconditional sequence" can never be rationally deduced from any amount of experience. His improvement on the position of Hume is only one of very superficial appearances.

(2) Brown, in his Inquiry into the Relation of Cause and Effect, clearly ranges himself on the side of those who reduce causality to a matter of invariable sequence. In Part I. sect. i. we read, "It is the mere relation of uniform antecedence, so important and so universally believed, which appears to me to constitute all that can be philosophically meant in the words power and causation, to whatever objects, material or spiritual, the words may be applied. . . . A cause, therefore, in the fullest definition that it philosophically admits, may be said to be that which precedes any change, and which, existing at any time in similar circumstances, has always been, and will always be, immediately followed by a similar change. Priority in the sequence observed, and invariableness of antecedence in the past and future sequences supposed, are the elements, and the only elements, combined in the notion of a cause." In rejecting what he conceives to be a definition, which makes power something more than invariable antecedence, he describes such power as "something mysterious, at once a part of the antecedence and yet not a part of it, an intermediate link in a chain of physical sequences, that is yet itself no part of the chain, of which it is said, notwithstanding, to be a link." Finally, in Part III. sect. v. he sets forth his view of the origin of our belief in uniform sequence or causation, which he attributes neither to perception nor to reasoning, nor to Hume's "customary association of ideas," but to a special intuition or instinct implanted by the Creator. "That with a providential view to the circumstances in which we are placed, our Divine Author has endowed us with certain instinctive tendencies, is as true as that He has endowed us with reason itself. We feel no astonishment in considering these when we discover the manifest advantage that arises from them; and of all the instincts with which we could be endowed there is not that which seems -- I will not say so advantageous, merely -- but so indispensable for the very continuance of our being, as that which points out to us the future, if I may so speak, before it has already begun to exist. it is wonderful indeed -- for what is not wonderful? -- that the internal revelation which this belief involves, should be given us like a voice of ceaseless and unerring prophecy. But when we consider who it was that formed man, then difficulty vanishes." This completes the positive statement of Brown's own view; but in the Fourth Part, where he proceeds to explain and reject Hume's theory, he ought to have been more struck by words so very like his own, as are these from the Inquiry, Part II. sect. vii.: "What stronger instance can be produced of the surprising ignorance and weakness of the understanding than the present? For surely if there be any relation among objects, which it imports us to know perfectly, 'tis that of cause and effect," Yet observation and reasoning are declared incompetent to produce this belief: we owe it to the instinctive force of custom, in which "those who delight in the discovery and contemplation of final causes have ample subject to employ their admiration." (scct. v. in fine.)

{1} Sum. i. q. xxxiii. a. i.

{2} Suarez. Metaphys. Disp. xii. sect. ii. n.

{3} Sum. i. q. xxxiii. a. i. ad 1.

{4} Active Powers. Essay i. c. vi.

{5} In the living organism the tendency to an organic end -- so clear that Clifford has called organization "the good " -- is much insisted on, as Zweckstrebigkeit. Zweckmauml;ssigkast.

{6} Even Reid thinks that there may be capricious acts "without all motive," and even "against all motive." (Works. p. ix.)

{7} The before is generally understood of time: but if any one believes that creation ab aeterno is possible, then he would have to accommodate the meaning of before, and of any other such term, to his own theory.

{8} In Lib. III. De Anima, c. ii; Sum. i. q. xlv. a. ii.

{9} Metaphys. Disp. xlviii. sect. ii. "Actia non est nisi quidam modus ipsius termini ilium constituens dependentem a sua cause: est habitudo viae ad terminum."

{10} Hence the otherness between cause and effect must be taken for neither more nor less than is required by the definition of active power, principium mutationis in alio quatenus est aliud, and of passive power, principium recipiens mutationem ab alia, quatenus est aliud.

{11} This important point, the source of so much confusion. is fully explained later where it will be seen how very vague is man's ordinary conception of the cause and the effect; where there are many causes and many effects. It is vague as with many logicians is the induction.

{12} Contra Gent. Lib. III c lxix.

{13} Pt. II. § 36. Cf. § 42.

{14} Recherche de la Vérité Liv. I. c. i.; Liv. VI. Pt. II. c. iii.

{15} Intellectual System Bk. I. c. iii. sect. xxxvii.

{16} Human Intellect, Bk. II. c. xxi. and c. xxvi. Cf. pp. 58, 59, 66, 67.

{17} Active Powers Essay i. c. v.

{18} Ibid. c. vi.

{19} Philosophy of the Human Mind, Pt. I. c. i. § ii.

{20} Some of the scholastics overlook this complexity, and try to bridge over the difficulty by a not very clear use of their distinction of effect in fieri and in facte esse. The effect in fieri is often a long succession of effects.

{21} Treatise, Bk. I. Pt. Ill, sect. iii.

{22} Remember that Hume allowed only two absolute contradictories, existence and non-existence: his name for them is, contraries.

{23} Active Powers, Essay i. c. iii.; Intellectual Powers, Essay vi. c. vi. § 6

{24} Works, p. 76.

{25} Logic, Bk. III. C. xxi. § 2 and § 4.

{26} "Le principe de causalité n'est qu'une application du principe de raison suffisante." (Ontologie, par A. H. Dupont, p. 366.)

{27} Works p. 8.

{28} Metaphys. Disp. xlviii. Lect. ii. § 12.

{29} St. Thomas, Contra Gent. Lib. III. c. lxix.

{30} Contra Gent. Lib. III. c. lxix.

{31} Recherche de la Vérité. Explications au Liv. VI. Pt. II. c. iii.

{32} Logic, Bk. III. c. v. § 2.

{33} Treatise, 13k. I. Pt. IV. sect. v.

{34} Aristotle, c. iv. pp. 90, 91.

{35} Mr. Balfour's Defence of Philosophic Doubt, c. iv. pp. 56, 57. Newton made it his second "rule of philosophizing." effectuum naturalium ejusdem generis eaedem sunt causae.

{36} Mr. Bain says." It seems to me, if I may venture an opinion, that for the present the vicariousness of causes must be practically recognized, at least in the more complex sciences; but that the particularity of causes, if I may use the expression, is really true." (Logic, Vol. II. pp. z6, seq., pp. 76, seq.)

{37} Metaphysics, Lect. xxxiii. p. 211. Lotze suggests a somewhat opposite theory, which gives the soul an internal power to repress the various motions stored up within it. (Metaphysics, Bk. III. c. ii. § 26.)

{38} In Metaphysics, Lib. IX. c. I. Lect. i.

{39} Sum. i. q. xlix. a. ii. ad 2.

{40} Contra Gent. Lib. II. c. ix.; De Potentia, q. vii. a. ix. ad 7.

{41} De Anima, Lib. V, c. iii.

{42} Aristotle's Psychology. p. 87.

{43} Treatise, Bk. I. Pt. II. sect. vi.

{44} Ibid. Pt. IV. sect. i.

{45} Note this word.

{46} Treatise, Pt. IV. sect. vii.

{47} Treatise, Bk. I. Pt. III. sect. xiv.

{48} Hence Mr. Huxley says. "Necessity is a shadow of the mind's own throwing."

{49} Treatise, Bk I. Pt. III. sect. xvi.

{50} Ibid. sect. xiv,

{51} Treatise, Bk. I. Pt. III. sect. xv.

{52} Logic, Bk. III. c. V. § 5.

{53} Does "superfluous" mean additional"?

{54} L.c. § 3.