Sunday, 3 November 2013

Question 86 – What our Intellects know in Material Things

Why this Question Matters

After the rigours of Ia.q85, this question sweeps up a number of particular issues to do with the cognition of material things. In particular it covers the cognition of singulars, of the infinite, of contingent things and of future things. In many ways, the content of this question represents a drawing together of issues that have been presented in various places of this treatise.

The Thread of the Argument

A1: Aquinas has already argued that the active intellect abstracts the universal from the phantasms presented to it by the sentient powers, and that the resulting intelligible species are retained in the passive intellect. This means that the intellectual powers acting on their own do not have cognition of singular concrete individuals but only of their universal aspects. Here Aquinas raises this observation to the status of an article, summarizing the arguments made so far and addressing some particular objections. The major point to be made is not that we do not have cognition of singulars, but that our cognition of singulars is not by means of the intellect alone. The intellect and the sentient powers act together in the cognition of singulars, so that the intellect has direct cognition of universals but only an indirect cognition of singulars.

A2: Right back in Ia.q7.a4 we saw Aquinas talking about the infinite as existing. Now it is time to consider the infinite as object of cognition; so, can we have cognition of infinitely many things? Aquinas’s answer revolves around the difference between a potential infinity and an actual infinity. If you were to start counting sheep in an effort to get to sleep, you would start “one sheep, two sheep, three sheep…” potentially with no limit if the insomnia were particularly bad that evening. This is an example of a potential infinity; you can count things as far as you have time to do so without theoretical limit. But you will never be in the situation of having counted an infinite number of sheep; you never get to the point of having cognition of an actual infinity of sheep. This is Aquinas’s position: we can have cognition of an arbitrary number of things but we cannot have cognition of a completed infinity.

The first objection claims that we can have cognition of something infinite; that is, God. Aquinas answers that there’s a subtle equivocation of language here. We would have an infinite material thing if there were no formal termination to its matter; that is, it would just go on for ever and ever. However, when we talk of God being infinite, we have to recall that His form has no connection with matter at all and therefore could not be terminated by an extent of matter. God’s form is per se infinite, rather than in reference to any matter. So a material infinite, if it existed, could not be known as the form is never terminated, but we can know something of the infinite God insofar as we grasp something of His form. Of course, our minds are limited in the extent to which we can grasp God’s form: in this life we can only grasp it by inference from the created order; in the next life by direct illumination by the divine essence. Still, by neither means can we comprehend that form (Ia.q12.a7).

A3: This third article is a strange little affair: Aquinas asks whether we can have cognition of contingent things. That is, can we have cognition of things that are able to be and not to be? As pretty much everything we perceive in the material world is contingent one has to ask why how this question could ever arise! The point is that, when we have cognition of things, we abstract the universal from the particular and the universal is not contingent in the same way that the object of cognition is. Now Aquinas does not take a Platonic view of form: forms do not exist in some third realm but exist only as instantiated. Still, the question has some force as this vase could go out of existence but the form of the vase could still exist (but not in a material mode) in some mind that had previous perception of it, or in a different exemplar of the vase produced by the same potter.

Aquinas argues that the sensory power has direct cognition of contingent things; we recall that the phantasm of an object of perception is still a phantasm of a particular material thing. The intellect only has an indirect cognition of a singular through the interaction of its universal knowledge of the thing with the sensory power’s individual knowledge of the thing. So our knowledge of a thing is made up of a complex of contingent stuff corresponding to the perception of the sensory powers together with cognition of universal necessary aspects of the thing in the intellect.

A4: To ask whether we can have cognition of future things, as this article does, is clearly naïve, as future things have not yet happened and therefore cannot be subject to the process of abstraction from phantasms formed from an object being perceived by the senses. However we might reasonably argue that we know that the sun is going to rise tomorrow; so the future can obviously be known in some sense. The universal that we abstract from the particular is abstracted from time and may therefore contribute in some way to knowledge of future things.

Aquinas recognises the connection with the third article concerning our knowledge of the contingent. Future things, after all, are contingent. He makes the key distinction between knowing future things in themselves and in their causes. Cognition of future things in themselves (that is, in their concrete existence) is known only to God who has an eternal intuitive vision of all time (Ia.q14.a13). However, we can know future things in their causes; through our scientific knowledge we know, to a certain extent, how the material world works and can therefore make reliable predictions about certain things (such as the sun rising tomorrow morning).

Handy Concepts

  • Our cognition of singulars occurs by means of the intellect returning to the phantasms made available to it by the sentient powers.
  • We have cognition of the potentially infinite but not of the actually infinite.
  • Our cognition of contingent things occurs by a combination of the universal retained by the intellect and the particular retained by the sentient powers.
  • We can know future things in their causes but not in themselves.


  • Aquinas’s teaching that we do not have purely intellectual cognition of singulars is often a stumbling block for those coming anew to his theory of mind. Perhaps the aspect for newcomers to concentrate on is that Aquinas has a very precise theory about how the different parts of our cognitive powers work together; perhaps our modern notion of intellect glosses over some of the distinctions between powers that Aquinas considers essential. So, it is not that we do not have cognition of singulars, but that we have cognition of singulars in a way that involves more than just the intellect. The intellect is a very particular part of our cognitive apparatus.
  • Perhaps Aquinas is rather optimistic in the second article in suggesting that we can have cognition of a potential infinity. My experience these days is that if I learn something new, something old falls out of the other side of my head.

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