Aristotle’s account in Categories can, with some
oversimplification, be expressed as follows. The primary
substances are individual objects, and they can be contrasted
with everything else—secondary substances and all other
predicables—because they are not predicable of or attributable
to anything else. Thus, Fido is a primary substance, and
dog—the secondary substance—can be predicated of
him. Fat, brown, and taller than Rover are
also predicable of him, but in a rather different way from that in
which dog is. Aristotle distinguishes between two kinds of
predicables, namely those that are ‘said of’ objects and
those that are ‘in’ objects. The interpretation of these
expressions is, as usually with Aristotelian cruxes, very
controversial, but a useful way of looking at it is as follows.
- The Forms
meet criterion (i)—ontological basicness—but in a slightly
eccentric way, because they do not, in a normal sense, constitute
things. - There are interpreters of Aristotle who think that this
kind of irreducibility is all that Aristotle means—or needs to
mean—by postulating an explanatory role for substantial form. - If we accept that the
question of what binds together the qualities of a macroscopic object
can be answered by appeal to the minute parts, the issue would then be
what binds the primary qualities of atoms. - In that
way, it will be possible to avoid the need to have two material
objects in the same place.
The indiscernibles argument then asserts that the identity of indiscernibles is violated, for example, by identical sheets of paper. All of their qualitative properties are the same (e.g. white, rectangular, 9 x 11 inches…) and thus, the argument claims, bundle theory and metaphysical realism cannot both be correct. Philosophers following this line of thought
included Fine (1999, 2010), Johnston (2006), Lowe (2011), Koslicki
(2008), Rea (2011) and Jaworski (2011, 2012). It is difficult to
provide a compact account of these philosophers’ positions, as
it can seem that all they have in common is a belief in some form of
restricted composition and a sense that the Aristotelian label
’hylomorphism’ helps to give their theories a pedigree.
In substance theory, a bare particular of an object is the element without which the object would not exist, that is, its substance, which exists independently from its properties, even if it is impossible for it to lack properties entirely. It is “bare” because it is considered without its properties and “particular” because it is not abstract. The properties that the substance has are said to inhere in the substance. René Descartes means by a substance an entity which exists in such a way that it needs no other entity in order to exist. However, he extends the term to created things, which need only the concurrence of God to exist.
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But failure to meet these standards is not
carelessness on Plato’s part. It reflects his emphasis on
criterion (i), together with his particular view about the way in
which forms are basic. If one is not satisfied with a bundle theory of substance, so that one
thinks that an individual substance is more than a collection of
properties, how is one to understand this ‘more’? The
deflationary answer is that a substance is a thing which has
properties, and that is all one needs to say (see, for example, Crane
and Farkas 2004, 143f, and Chisholm 1969). An object is not composed
of properties and some further ingredient—the
‘thingy’ bit—an object is something that simply has
properties.
The concept of substance figures centrally in a positive way for the
rationalist philosophers, in a way that it does not for the
empiricists. The rationalists’ substances are not, however, the
individual objects of everyday life. As we have seen, substances are the paradigm subjects of predication
and change, so (iii) and (iv) are met. As Aristotle’s substances
are individual things and kinds of things (v) is met.
Chemical processes involving the substrate(s) are catalysed by enzymes. The active site transforms the substrate into one or more products, which are then released. After that, the active site is free to take a new substrate molecule.
- The substrate is a molecule on which an enzyme functions in biochemistry.
- If either of the above accounts are successful, substances, properties
and events are distinguished. - Perhaps it is more profitable to ask whether, in his own terms, Locke
ought to have accepted bare substratum. - The bundle theorist’s principal objections to substance theory concern the bare particulars of a substance, which substance theory considers independently of the substance’s properties.
- For example, rock is a substrate for fungi, a page is a substrate on which ink adheres, and NaCl is a substrate for the chemical reaction.
Fat and the others are described as being
in because they pick out a constituent feature that could be said
to be, in a logical though not a physical sense, part of, or
in him. This association of substance with kinds carries
over into a use of the term, which is perhaps more scientific,
especially chemical, than philosophical. This is the conception
according to which substances are kinds of stuff. Examples of this usage are water,
hydrogen, copper, granite or
ectoplasm.
David Wiggins (1967, 1980, 2001) has made a sustained attempt to prove
that these two objectives necessarily go together and to make the
Aristotelian notion of substance, even including its bias towards the
biological, central to our practice of individuating objects. One objection often made against the theory is that bundles are
mereological sums, rather like Locke’s ‘masses of
matter’, and that, therefore, any change of property is a change
in the identity of the object. Various forms of essentialist solutions
to this problem have been suggested, for example, by Simons (1994),
and Barker and Jago (2018).
Substrate
But the concept of substance is essentially a philosophical term of
art. Its uses in ordinary language tend to derive, often in a rather
distorted way, from the philosophical senses. But such ‘individual substances’ are
never termed ‘substances’ outside philosophy. There are certain kinds of counter-example that Wiggins does not
discuss in print.
Even if dogs are
wholly physical objects and even if all the atoms in dogs follow very
precise laws of physics, nevertheless when doing the biology of dogs
one will need concepts not to be found in a physics textbook. This is
not for mere shorthand convenience, but because of the kinds of things
in which, for example, the biologist or veterinary scientist is
interested. There are interpreters of Aristotle who think that this
kind of irreducibility is all that Aristotle means—or needs to
mean—by postulating an explanatory role for substantial form. His theory is at least neutral on the question of whether there is a
closed system at the level of basic physics (Nussbaum 1978, 1984). John Locke views substance through a corpuscularian lens where it exhibits two types of qualities which both stem from a source.
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However, this doctrine was rejected by Pope Paul VI in his encyclical Mysterium fidei. But Johnston’s notion of a ‘principle of unity’
turns out to be so generous that his theory almost collapses into
Lewis’s. As we shall see, the idea that there is a real unity that is passed on
through the life of an object or through any principle of organisation
is something that what is substratum Hume criticises and rejects. The positions, sequences, structures, and properties of these residues create a very specific chemical environment within the active site. A specific chemical substrate matches this site like a jigsaw puzzle piece and makes the enzyme specific to its substrate. In biochemistry, the substrate is a molecule upon which an enzyme acts.
Notable examples of possible substrate or superstrate influence
There is one important context, however, where Locke does not appear
to talk in a conventionalist way about sortal identity, but in a way
that seems to be reminiscent of substantial forms. As such, any change of particle
constitutes a new object, for a mereological sum is individuated by
its parts and a change of parts means a change of the object
constituted by those parts. Treating ordinary, non-living, bodies as
complex enduring objects is a matter of convention determined by the
concepts we happen to possess.
The Forms
meet criterion (i)—ontological basicness—but in a slightly
eccentric way, because they do not, in a normal sense, constitute
things. They are not, in the intended senses, the subjects
of predication, and in no sense the subjects of change, so they do
badly on (iii) and (iv). They do not do well on (v) for they are not
individual things in any normal sense, though they are individuals, of
a very unusual kind. (Aristotle’s main criticism of
Plato’s Forms was that they are a bastard confusion of universal
and particular; see Fine 1993.) They are in no way kinds of stuff,
hence failing (vi).
Meaning of substratum in English
Of course, it is not an accident that
nature works that way, but neither is it a conceptual requirement. Wiggins’s original proof was a priori, and it should allow no
exceptions. Wiggins’s response to this example (in personal
communication) is that the sword-stick ceases to exist when it loses
its ability to function as a sword and is replaced by a walking stick. It embodies the principle
that if anything is both an F and a G, where
F and G are normally ordinary sortals, then it is
really an F/G and ceases to exist if it loses either
its F or its G features and is replaced by something
that is either just an F or just a G. The most obvious is
that it does not, as stated, distinguish between substances and
events.
Origin of substratum
It might seem natural to think—and it was formerly a
well established maxim—that there can be only one solid physical
thing at one place at a given time. Someone impressed by the idea that
two bodies cannot be in the same place at the same time might think it
more natural to say that there are two different ways of
conceptualising the material presence at that point, than that there
are two material things. That way it is easy to see why two ten pound
objects need not add up to twenty pounds when put together.