Note that it does not follow from these assumptions that the substantial form ofx
exists only in worlds in whichxexists. If forms can be detached in this way, then the
ontic ground of the total propositional essence ofxcan exist even whenxdoes not.
And in which case, that total propositional essence ofxis true in these worlds. If
forms are detachable in this way, are they necessary beings? In which case, true
essentialist claims are necessarily true.
Defenders of substantial forms have historically been divided into two camps:
those who believe that a given object has one substantial form versus those who
believe that it has a plurality of substantial forms.^60 Why believe in a plurality of
substantial forms? Consider a human person. She is not merely a lump of matter, but
rather she is an organized corporeal entity with many capacities. Her rational
substantial form is what makes her a human person, which, let us say, is what she
strictly essentially is. But were she to suffer a terrible accident and lose her rationality,
something might still remain, e.g., a living animal, which in turn is a hylomorphic
compound. Since some informed material thing persisted, there must have been an
animal (or sensitive) substantial form all along.^61
Suppose an object has multiple substantial forms. Is each form an ontic essence for
that object? Are any of its forms a good candidate for being the ultimate ontic essence
of the object? I believe the answer to thefirst question is“no,”which is also why the
answer to the second question is“yes.”^62
My impression is that the proponents of multiple forms believe that they are
hierarchically ordered. Consider a human being with three substantial forms, one of
which is her rational substantial form, another of which is her animal/sensitive
substantial form, and,finally, one of which is her material/corporeal substantial
form.^63 Her possession of a rational substantial form ensures her possession of an
animal form, which in turn ensures the possession of her material substantial form.
But it’s not the case that each form is an ontic ground for her essence. Rather, there
are two possibilities. Thefirst possibility is that the ontic ground for her essence is
solely the rational form, which grounds her possession of the other two forms as well.
identified with substantial form or is at least“fully expressed”by substantial form. Galluzzo (2013: 6) says
that, for Averroes,“the essence of material substances is exhausted by their form alone.”
(^60) See chapters 24 and 25 of Pasnau (2011) for a riveting discussion of the debate over whether created
things have one substantial form or many. See also Kok (2014: 534 61 – 5).
62 See Pasnau (2011: 580–8) for more on the twists and turns of this kind of argument.
De Raeymaeker (1957: 162) appears to claim that substantial forms are the grounds of essences; he
also addresses in footnote 9 a worry about what to say if things have more than one substantial form—
which form is then the ground of essence? The worry about multiple substantial forms seems analogous to
a worry Descartes has about principle attributes. Descartes (1992: 210–11),PrinciplesI.53, tells us that the
principle attribute of a thing is its“principle property which constitutes its nature and essence, and to
which all its other properties are referred.”Descartes (1992: 398) later claims inComments on a Certain
Broadsheetthat, if something had more than one principle attribute, it would have more than one essence,
which is impossible. See Hoffman (2011) for further discussion. 63
This is the sort of view defended by Ockham, according to Pasnau (2011: 577).