A mechanist materialist would probably then appeal to the atom as the prime building block of DNA and hence the cat. Of course, atoms are composed of sub-atomic particles, which demand explanation. These particles are also made of sub-particles, and so on… Eventually, the materialist must arrive at some particle which is the fundamental reality of the cat; the one thing that makes the cat real. However, even if he were to stop his sub-atomic chain at such a particle (such as pure energy or super-strings) he would still have to explain where the particle derives its “reality”. In this event, the materialist would just admit that the energy particle (for arguments sake lets call it a super-string) just is real; it has no explanation for itself and must be a completely simple reality. If he did this he would find himself agreeing with Aristotle. Why? The reason is that the materialist will have agreed that the super-string is a fundamental reality. The super string has mass, quality (such as brightness or texture), quantity and possibly other modes of existence called accidents by Aristotelian thinkers. The materialist must agree that the fundamental particle (the super-string) has accidents, otherwise where does the quantity, quality, position, posture, etc. of the cat come from? If the materialist agrees to the fact that the super-string is a fundamental reality with accidental qualities, then he has just defined an Aristotelian object. His object has substance (a primary mode of being which fundamentally just is) inhered with accidents (secondary modes of being which give the substance discernable characteristics). In the end, the materialist will be forced to admit the reality of substance and accidents over the philosophy of an endless string of mechanistic materialism. We can also simply say that the cat just is a simple substance inhered with accidents that are divisible into parts (DNA, proteins, atoms, quarks, super-strings, etc.) The cat is defined as a whole rather than a sum of parts. The cat is fundamentally composed of primary matter with the form of a cat. The parts (such as cat DNA and its constituent atoms) are also feline since the form of the cat is inherent in every part of the cat. The substance of the cat determines the parts to be what they are. An individual atom separate from the form of the cat is substantially different because the substance of the atom is atomic, but an atom in a cat is only part of the whole: therefore its substance is feline. The bottom line is that a whole must be defined first before parts can be predicated to it.