Disputation 5, Section 4:
Is the substantial form the principle of individuation in material substances?
- I. The two principal arguments (nn. 1-2)
- "The principle of individuation has to be something which (i) intrinsically
constitutes this substance and which (ii) is maximally proper to the
substance. Thus, by reason of the first property it has to be something
substantival. For accidents, as has been said repeatedly, constitute neither
substance nor this substance, since this substance, insofar as it is a this, is a
per se and substantival being. On the other hand, by reason of the second
property the principle in question cannot be matter, but [must be] form. For
this matter is not maximally proper to this individual, since it can exist
under other forms as well. Therefore, form is the principle of individuation."
- "The principle of unity is the same as the principle of entitas, since, as St.
Thomas says, 'Each thing has esse and individuation according to the same
[principle].' But each thing has its esse properly from its form. Therefore, it
also has its individual unity from the form. The major premise is obvious
from the fact that unity is a property that follows upon esse, and it adds to
the latter only a negation; therefore, unity cannot have a positive and real
principle other than that which is the principle of the entitas itself."
- II. The evaluation (nn. 3-6)
- The main objection to this position is that the two arguments just adduced
prove at most that form is a principle of individual unity, but not that it is
the only such principle. For the matter, too, constitutes the substance
intrinsically and is thus at least part of the principle of individual unity.
- One reply to this objection is that the form individuates not only the
substance but the matter as well.
- However, Suarez criticizes this reply in various ways. For one thing, it
makes mincemeat out of the Aristotelian contention that generation is a
genuine change because the very same matter is at first under one form and
then under another. But this cannot be true if the form makes the matter it
informs to be this matter. Instead, the matter at the terminus a quo of the
change would not be the same as the matter at the terminus ad quem.
- "It is true, to be sure, that the adequate intrinsic cause of a material
substance's individual unity is, as the objection concludes, both the form and
the matter. However, if these two [principles] are compared with one
another, the principal cause of this unity is the form, and it is in this sense
that it is especially attributed to the form that it is the principle of
individuation." For the form completes the individual in the same way that
the specific difference (form) completes the species. "The common way of
thinking and talking confirms this. For if, say, to Peter's soul there is united
a body composed of matter that is distinct from the body that he previously
had, then even though this latter composite is not identical in every part
with the one that existed before, the individual is still called the same
individual, absolutely speaking, by reason of the same soul." But the
converse does not hold. This indicates that the form, rather than the matter,
is the principal principle of individuation.
- Suarez is not utterly impressed by this reply, mainly because it still leaves
open the question: What makes this form itself a this? "It is not form as
such, but rather that by virtue of which the form is a this, that is the
principle of individuation." And some argue that this latter thing is the
- Now Suarez himself, of course, does not accept this answer to the question.
Indeed, he tries to show that exactly the same question arises with respect to
the matter. "Thus, all the arguments adduced above can prove the same
thing about the matter that they intend to prove about the form. For on this
score there is a sort of parity between the matter and the form. And from
another angle the matter surpasses the form only because it provides a
certain occasion for producing various and individual forms, whereas the
form surpasses the matter because it principally constitutes the individual,
because it is more proper to it, and because it is the matter that exists
because of the form rather than vice versa." Nonetheless, he believes that
even if 'matter' is a bad answer to the question, the question itself is
nonetheless legitimate and requires a reply that takes us beyond the account
of individuation proposed in this section.
- III. The resolution (n. 7)
- "Thus the present position, as we have explained it, is rather plausible and gets
close to the truth. Nonetheless, one should say without qualification that the form
alone is not the full and adequate principle of individuation for material things, if
we are talking about their entire entitas--even though it is the principal principle
and is thus sometimes, according to the formal mode of speaking, judged sufficient
for denominating that same individual. All of this will be clarified and proved at
length in section 6."