Michael Egnor

Goodness gracious, this stuff never stops. From Plus Magazine:

Can cats do logic?

Of course they can! Any cat knows that pawing the box of cat biscuits will make it fall over and the biscuits pour out. That’s a firm grip on the law of cause and effect. But what if the box is empty? Can cats deduce this fact from the sound or feel of the box, or are they simply taking their chances? How much can cats infer from incomplete information?

It’s a question that has recently received a partial answer in a (refreshingly simple) experiment conducted by scientists in Japan… Thirty cats took part in the study, and here is how the researchers tested them. They presented each cat with a container that did or did not rattle when shaken. The container was then turned over and an object did or did not fall out — but not always in line with what you’d expect. In some cases a rattling box did reveal an object when turned over, but in others it didn’t. Conversely, a non-rattling box could also reveal an object, or not. Once the container had been turned over, the cat was allowed to go and explore. If cats do understand the connection between rattling and the existence of objects and if they understand gravity, then, so the reasoning goes, they should act surprised when the unphysical situation occurs.

This, the researchers say, is exactly what happened. Cats spent more time looking at the containers that didn’t confirm with the laws of physics, than they did at those which did. This suggests they do understand the causal connection between sound and object and have a grasp on gravity… More generally the study sheds light on how ecological factors influence animals’ ability to make inferences from sound. It doesn’t indicate that cats are likely to take up mathematical logic any time soon.

Of course cats can’t do logic, mathematical or otherwise, and they never will. Cats can be clever, and can make inferences about things in their environment. But they don’t do logic. Because they’re cats.

Logic is a system of abstract rule-based inferences. The key word is abstract. Logic is abstracted from particulars. To wit, modus ponens works for any particulars:

If P then Q.

P.

Therefore Q.

A logical statement is true inherently, independently of the particulars that occupy the place-holders. Logic is abstract thought. Logic is contemplation of universals, not particulars.

What distinguishes men from animals is this: men, but not animals, can contemplate universals, independently of particulars. Animals cannot contemplate universals. Animal thought is always tied to particular things.

This rudimentary fact about animal and human minds was noted by Aristotle, and was common knowledge for a couple thousand years. Moderns have forgotten it, and it has led to a morass of confusion about animal minds and the differences between human and animal thought.

Animals are capable of thought only about particular things, although animal thought about particular things can be surprisingly sophisticated. This ability of animals (and people) to think about particulars was called sensus communis and identified by Aristotle in De Anima (Book III, Chapter 2, 425a27). It is the basis for the term “common sense,” although in philosophy of the mind it has a more precise meaning than in its everyday usage. It means the ability to think about particular things known via perception, especially about particulars known by more than one sense, and to integrate perceptions and make inferences about the particulars.

Sensus communis is the power by which an animal (or a man) decides to select the larger bowl of food rather than the smaller, for example. Such selection does not mean the thinker has an abstract concept of quantity, abstracted from the particular bowls of food in front of it. Animals don’t measure their food. They don’t abstract universal concepts such as volume or weight from their perception of food. But they can compare bowls of food they perceive, and make judgements based on the comparisons. None of this entails abstract thought. All animal thought is tied to particular things.

So cats don’t understand gravity, as an abstract concept. They can learn to expect things to fall to the floor, and they are surprised when things don’t, but that doesn’t mean that cats are contemplating Newton’s equation of gravitation or tensor calculus of the curvature of spacetime. Animal thought lacks abstraction. Animals think about particulars, and the qualities and relations of particulars. Animal thought can be quite clever and sophisticated, but it is always grounded in particular things.

There has never been a demonstration of an animal who is capable of abstract thought about universals, unlinked to particulars. In fact, an animal cannot think about universals, for the simple reason that animals have no language. Contemplation of universals, abstracted from particulars, presupposes language, because thought without particulars cannot be done without language. How would an animal contemplate mercy or justice or imaginary numbers without a language with which to express the abstract concept? All thought is about something. If an animal has no language and tries to think about a universal without instantiation in a particular, what exactly would the animal be thinking about?

Animals can think about particulars without language, because particulars provide an object that is necessary to have an intentional thought — a thought about something. But without language, animals are incapable of thinking about anything that is not a particular. Animals think about their owner, but not about ownership. They think about food, but not about nutrition.

Men can think abstractly and have language. Language is what makes abstract thought possible. This is the root of what makes us human. We don’t have language in order to communicate with other people (contra evolutionary fairy tales about screeching monkeys and group selection), although language is certainly useful for communication. We have language in order to think abstractly. Men have spiritual souls, and we are able to contemplate abstractions like universals independently of particular things.

Abstract thought is an immaterial power unique to the human soul, and language is necessary to it.