7. Is Logic to be Considered a Science or an Art? -- Is logic a speculative or a practical science? Speculative science stops at the knowledge of its object; practical science makes that knowledge subservient to an ulterior action or work. "The end of the speculative is truth; the end of the operative, or practical, is action." The logician does not study acts of thought merely for the disinterested pleasure of knowing their co-ordination; he puts his science to the ulterior use of directing mental operations. In this sense some hold, and with reason, that logic is a practical science. -- Others, taking a higher point of view, say that logic is a speculative science, because the direction of mental operations is itself subordinate to the knowledge of truth. St. Thomas takes this view when he says: "In speculative matters the rational dialectic science is one thing . . . the demonstrative, another."^{1}

Logic is also an art, if by this we understand a body of practical rules, for the guidance of action.^{2}

{1} Summa Theol.. 2a 2ae, q. 51, art. 2, ad 3.

{2} "Other animals", he says, "are prompted to their acts by a certain natural instinct, but man is directed in what he does by the judgment of his reason. For this reason various arts serve for the easy and orderly execution of human acts. For an art appears to be nothing else but a fixed disposition of reason by which human acts arrive at their due end by way of calculated means. Now reason not only can direct the acts of the subordinate parts, but is also adapted to direct its own function. For it is the property of the intellective part to reflect upon itself: the intellect understands itself, and in like manner the reasoning faculty can reason about its own act. As, therefore, the art of building or of carpentry comes from the fact that the reasoning faculty reasons about the act of the hand, and man is thereby enabled to perform acts of this kind with ease and with well ordered effort, so, also, there must be some art by which the act of the reason itself may be directed, by which man may proceed easily and correctly in the very act of reasoning. And this is the art of logic, i. e., the rational science. Nor is it rational only because it is according to reason, which is a common characteristic of all arts, but also because it deals with the very act of the reason as its proper matter. And therefore it seems to be the art of arts, because it directs us in the act of the reason, from which act all acts proceed." Post. Analyt., lect. I.