In Book III of On the Soul, Aristotle argues that the intellect does not have a bodily organ:
Therefore, since everything is a possible object of thought, mind in order, as Anaxagoras says, to dominate, that is, to know, must be pure from all admixture; for the co-presence of what is alien to its nature is a hindrance and a block: it follows that it too, like the sensitive part, can have no nature of its own, other than that of having a certain capacity. Thus that in the soul which is called mind (by mind I mean that whereby the soul thinks and judges) is, before it thinks, not actually any real thing. For this reason it cannot reasonably be regarded as blended with the body: if so, it would acquire some quality, e.g. warmth or cold, or even have an organ like the sensitive faculty: as it is, it has none. It was a good idea to call the soul ‘the place of forms’, though (1) this description holds only of the intellective soul, and (2) even this is the forms only potentially, not actually.
Observation of the sense-organs and their employment reveals a distinction between the impassibility of the sensitive and that of the intellective faculty. After strong stimulation of a sense we are less able to exercise it than before, as e.g. in the case of a loud sound we cannot hear easily immediately after, or in the case of a bright colour or a powerful odour we cannot see or smell, but in the case of mind thought about an object that is highly intelligible renders it more and not less able afterwards to think objects that are less intelligible: the reason is that while the faculty of sensation is dependent upon the body, mind is separable from it.
There are two arguments here, one from the fact that the mind can understand at all, and the other from the effect of thinking about highly intelligible things.
St. Thomas explains the first argument:
The following argument may make this point clear. Anything that is in potency with respect to an object, and able to receive it into itself, is, as such, without that object; thus the pupil of the eye, being potential to colours and able to receive them, is itself colourless. But our intellect is so related to the objects it understands that it is in potency with respect to them, and capable of being affected by them (as sense is related to sensible objects). Therefore it must itself lack all those things which of its nature it understands. Since then it naturally understands all sensible and bodily things, it must be lacking in every bodily nature; just as the sense of sight, being able to know colour, lacks all colour. If sight itself had any particular colour, this colour would prevent it from seeing other colours, just as the tongue of a feverish man, being coated with a bitter moisture, cannot taste anything sweet. In the same way then, if the intellect were restricted to any particular nature, this connatural restriction would prevent it from knowing other natures. Hence he says: ‘What appeared inwardly would prevent and impede’ (its knowledge of) ‘what was without’; i.e. it would get in the way of the intellect, and veil it so to say, and prevent it from inspecting other things. He calls ‘the inwardly appearing’ whatever might be supposed to be intrinsic and co-natural to the intellect and which, so long as it ‘appeared’ therein would necessarily prevent the understanding of anything else; rather as we might say that the bitter moisture was an ‘inwardly appearing’ factor in a fevered tongue.
This is similar to St. Thomas’s suggestion elsewhere that matter and understanding are intrinsically opposed to one another. I cautioned the reader there about taking such an argument as definitive too quickly, and I would do the same here. Consider the argument about sensation: it is true enough that the pupil isn’t colored, and that perception of temperature is relative to the temperature of the organ of touch, or some aspects of it, which suggests that heat in the organ impedes the sensation of heat. On the other hand, the optic nerve and the visual cortex are arguably even more necessary to the sense of sight than the pupil, and they most certainly are not colorless. Taking this into consideration, the facts about the pupil, and the way touch functions, and so on, seem like facts that should be taken into consideration, but do not even come to close to establishing as a fact that the intellect does not have an organ.
Likewise, with the second argument, Aristotle is certainly pointing to a difference between the intellect and the senses, even if this argument might need qualification, since one does tire even of thinking. But saying that the intellect is not merely another sense is one thing, and saying that it does not have an organ at all is another.
We previously considered Sean Collins’s discussion Aristotle and the history of science. Following on one of the passages quoted in the linked post, Collins continues:
I said above that Aristotle thinks somewhat Platonically “despite himself.” He himself is very remarkably aware that matter will make a difference in the account of things, even if the extent of the difference remains as yet unknown. And Aristotle makes, in this connection, a distinction which is well known to the scholastic tradition, but not equally well understood: that, namely, between the “logical” consideration of a question, and the “physical” consideration of it. Why make that distinction? Its basis lies in the discovery that matter is a genuine principle. For, on the one hand, the mind and its act are immaterial; but the things to be known in the physical world are material. It becomes necessary, therefore, for the mind to “go out of itself,” as it were, in the effort to know things. This is precisely what gives rise to what is called the “order of concretion.”
But how much “going out of itself” will be necessary, or precisely how that is to be done, is not something that can be known without experience — the experience, as it turns out, not merely of an individual but of an entire tradition of thought. Here I am speaking of history, and history has, indeed, everything to do with what I am talking about. Aristotle’s disciples are not always as perspicacious as their master was. Some of them suppose that they should follow the master blindly in the supposition that history has no significant bearing on the “disciplines.” That supposition amounts, at least implicitly, to a still deeper assumption: the assumption, namely, that the materiality of human nature, and of the cosmos, is not so significant as to warrant a suspicion that historical time is implicated in the material essence of things. Aristotle did not think of time as essentially historical in the sense I am speaking of here. The discovery that it was essentially historical was not yet attainable.
I would argue that Sean Collins should consider how similar considerations would apply to his remark that “the mind and its act are immaterial.” Perhaps we know in a general way that sensation is more immaterial than growth, but we do not think that sensation therefore does not involve an organ. How confident should one be that the mind does not use an organ based on such general considerations? Just as there is a difference between the “logical” consideration of time and motion and their “physical” consideration, so there might be a similar difference between two kinds of consideration of the mind.
Elsewhere, Collins criticizes a certain kind of criticism of science:
We do encounter the atomists, who argue to a certain complexity in material things. Most of our sophomore year’s natural science is taken up with them. But what do we do with them? The only atomists we read are the early ones, who are only just beginning to discover evidence for atoms. The evidence they possess for atoms is still weak enough so that we often think we can take refuge in general statements about the hypothetical nature of modern science. In other words, without much consideration, we are tempted to write modern science off, so that we can get back to this thing we call philosophy.
Some may find that description a little stark, but at any rate, right here at the start, I want to note parenthetically that such a dismissal would be far less likely if we did not often confuse experimental science with the most common philosophical account of contemporary science. That most common philosophical account is based largely on the very early and incomplete developments of science, along with an offshoot of Humean philosophy which came into vogue mainly through Ernst Mach. But if we look at contemporary science as it really is today, and take care to set aside accidental associations it has with various dubious philosophies, we find a completely wonderful and astonishing growth of understanding of the physical structure not only of material substances, but of the entire cosmos. And so while some of us discuss at the lunch table whether the hypothesis of atoms is viable, physicists and engineers around the world make nanotubes and other lovely little structures, even machines, out of actual atoms of various elements such as carbon.
And likewise during such discussions, neuroscientists discuss which parts of the brain are responsible for abstract thought.
When we discussed the mixing of wine and water, we noted how many difficulties could arise when you consider a process in detail, which you might not notice simply with a general consideration. The same thing will certainly happen in the consideration of how the mind works. For example, how am I choosing these words as I type? I do not have the time to consider a vast list of alternatives for each word, even though there would frequently be several possibilities, and sometimes I do think of more than one. Other times I go back and change a word or two, or more. But most of the words are coming to me as though by magic, without any conscious thought. Where is this coming from?
The selection of these words is almost certainly being done by a part of my brain. A sign of this is that those with transcortical motor aphasia have great difficulty selecting words, but do not have a problem with understanding.
This is only one small element of a vast interconnected process which is involved in understanding, thinking, and speaking. And precisely because there is a very complex process here which is not completely understood, the statement, “well, these elements are organic, but there is also some non-organic element involved,” cannot be proved to be false in a scientific manner, at least at this time. But it also cannot be proved to be true, and if it did turn out to be true, there would have to be concrete relationships between that element and all the other elements. What would be the contribution of the immaterial element? What would happen if it were lacking, or if that question does not make sense, because it cannot be lacking, why can it not be lacking?