Why this Question Matters
After having considered the powers of the soul in general and the specific sentient powers of the soul in particular, Aquinas now turns his attention to the intellect. Although this is a very lengthy question, with thirteen articles, he will have only just begun consideration of the intellect by its end. Questions Ia.q84-9 will be devoted to the specific ways in which the intellect functions in detail; this question deals with an overview of the intellective powers of the soul.
The intellect is what differentiates humans from other animals. The fact that our intellects give us understanding of universals, extracted from the perception of concrete particulars, affects both the ways in which our sentient powers function with respect to their particular objects as well as the ways in which our appetites reach out to those objects. If we return to Boethius’s definition of a person as “an individual substance of a rational nature”, we see that to a very great extent, intellect is what defines us.
The Thread of the Argument
A1: In the summa theologiae we often see the pattern whereby the opening article of a question answers the most important issues to do with that question and the remaining articles work out the details, frame the corollaries or simply mop up loose ends. In this extraordinarily long question about the intellect, however, this pattern is broken. The opening article asks whether the intellect is a power of the soul or whether it is the soul’s essence; a question that has already been answered in Ia.q77.a1! Indeed, the answer given is simply a reiteration of the answer given previously; it is only in God that intellect and essence coincide, as the only time the immediate principle of an operation is the essence of a thing is when the operation is the thing’s esse.
One looks to the objections to see if Aquinas has taken the opportunity to knock down some powerful new counter argument; but the objections are all simple misunderstandings or equivocations. It appears that Aquinas just wanted to reiterate the fundamental nature of the intellect as an introduction to the meaty issues to come.
A2: The function of the intellect is to abstract the universal features, the quiddity, of the object of perception from the intentional species provided by the sensitive powers of the soul and to receive and retain them. We will see that this means that there is both an active and a passive component of the intellect. In this article, Aquinas considers the passive (or potential) part of the intellect; in the next he will turn to the active or agent intellect.
In considering whether we can think of the intellect as a passive power, Aquinas looks at the meaning of the word passive; he promptly eliminates a couple of candidate meanings from those which might apply to the intellect. For his purposes he interested in taking passive to mean anything that passes from potentiality to actuality. The reason for this is as follows. The intellect of God is purely actual in creatively knowing all things real or virtual. No created intellect, however, can be in actuality to the entirety of knowledge; otherwise it would not be a finite being. The knowledge that the angels have is in actuality because of the way that they know things, but they know only what has been infused within them. In contrast, the created intellect of the human being has to pass from potentiality to actuality in learning something new. Quoting Aristotle, Aquinas points out that our intellects start “like a clean tablet on which nothing is written”.
A3: If the intellect was purely passive, then we would have a problem. The end result of the process of sensation is an intentional form in the soul that is the form of a concrete individual thing. As such it is still individuated by the matter that it informs it in the actual individual thing. In order for something intelligible to be received in the passive intellect another stage has to be gone through; the quiddity of the individual object has to be abstracted in order to arrive at the intelligible species that will be impressed upon and retained in the passive intellect. The power that performs this function is called the agent intellect.
Aquinas points out that under Plato’s understanding of forms, there would be no need for such an active power. In Plato’s system forms of things exist independently of the things themselves; that is, apart from matter, and are therefore directly intelligible to the (passive) intellect. For Aristotle, the forms of concrete things cannot exist independently of the things themselves; there needs to be an active power abstracting the intelligible content from the concrete object.
The first objection attempts to make a parallel between intellection and sensation; there is no need for an active power to extract the sensible species from a concrete object, why therefore need one be posited for intellection? The difference is that the concrete object itself provides the actuality that moves the sensitive powers to actuality, so there is no need for an active sensitive power. But the intellect has to work on what is produced by the sensitive powers and this has not been entirely removed from materiality; the sense organs at the very least are still involved. Actuality and potentiality work in the same genus; in order for a potentiality to be moved to an actuality by some being in actuality, that being has to be in the same genus as the potentiality. Therefore the materially involved sensitive species cannot move the immaterial potentiality of the intellect to actuality; there needs to be an immaterial agent in actuality in order for that to happen.
A4: In the third article we have seen that there must be an active power moving the passive intellect; but does this power have to be part of the soul? To our eyes, this may seem a very strange question to ask but in the middle age it was a live question. The function of the active intellect is so extraordinary, abstracting the quiddity of objects from the phantasms provided by the senses, and so particular to the human condition, that one might easily attribute it to the divine. As psalm 4 says: “The light of your countenance, Oh Lord, is signed upon us”. Indeed, Aquinas inherits from Augustine the tradition of explaining intellectual understanding in terms of divine illumination: it is God himself who acts directly on our intellects so that we get to the heart of what things really are.
Aquinas sees things differently than this tradition. He argues, gently in this article but more forcefully elsewhere, that the act of understanding belongs genuinely to us. Here he says “We know this (that the active intellect illuminates phantasms) when we perceive ourselves abstracting universal forms from particular conditions”. His point is a vital one; one that must be made in face of any argument that would underestimate the importance of the fact of the experiencing subject. It is I that understands what I am currently understanding and I am experiencing the fact that I am understanding. Any theory of mind that does not explain the subjective nature of the experiencing subject is worthless.
Applying this principle to the question in hand we see that the active part of my intellect must belong to me and, in particular, to my soul. That is not the end of it, though. The active intellect begins to look very much like a first mover; something that sits at the start of a chain of per se causation. However, this is where divine illumination correctly sits; God is the only first mover in the universe and it is He that moves our active intellects to the act of illuminating the phantasms.
A5: One of the medieval theories that had much purchase at the time St. Thomas was writing was the idea that the agent intellect was a unity, shared between all human beings. The fact that this was such an important theory explains why he this out to have its own article; he has, of course, already answered the question. The agent intellect is a power of the soul of each individual person; each person’s illumination of the phantasms is personal. Therefore the agent intellect is not shared between human beings, as one and the same power cannot be shared between substances.
One of the curious facts about human beings working to support the idea of the single agent intellect is that we all share in the most fundamental conceptions of the intellect; after all, if we didn’t there could be no communication between us. However, Aquinas argues in the reply to the third objection that this is simply down to the fact that humans are all in one species; everyone shares in an action that is derived from the nature of the species.
A6: We saw in Ia.q78.a4 that the sentient part of the soul possesses a power of memory; past sensory experiences can be brought to mind and the common sense acting together with the imagination can re-form phantasms (or can imagine new phantasms based on past experience) upon which the active intellect can act. Aquinas now asks whether there is a corresponding power of memory in the intellective part of the soul. More specifically, does the intellect have the ability to conserve intelligible species that are not currently being apprehended?
Aquinas spends some time discussing the point of view put forward by Avicenna in his commentary on Aristotle’s de anima. According to Avicenna, memory is purely a function of the sentient soul; if the intellect wishes to turn to a recollection of the past, the active intellect has to return to the phantasms provided by the internal sensory powers. The passive intellect retains nothing; it can only consider what the active intellect is currently presenting to it. Aquinas argues that this opinion is inconsistent with what Aristotle says in the de anima. The passive intellect receives and retains the intelligible species presented to it by the active intellect. The fact that an intelligible species is present in the passive intellect does not mean that it is always currently being comprehended; rather the passive intellect is in first potentiality for receiving intelligible forms in the first place and in second potentiality for actually considering them at any particular moment. I may have the ability to speak in French, but that does not imply that I am actually speaking in French right now.
So, there is the power of memory in the intellect insofar as the passive intellect retains the intelligible species impressed upon it by the active intellect. However, we must note that the passive intellect retains the quiddity of things and not their instantiation as concrete objects. It has an intellective understanding of man insofar as he is a man, for example. For the intellect to consider the temporal context of the intelligible species it has retained, it needs to turn to the sentient part of the soul which remembers both that it was sensing at a past time and that it was sensing a man at that past time.
In the reply to the second objection, Aquinas turns to the reflexivity of intellection. The intellect has an intellective understanding of itself as a particular intellect. What is more, it has an intellectual understanding of a particular act of its own intellectual understanding that exists at a particular time. So, although the temporal context of the object of the intellect does not belong per se to the intellect (this is supplied in conjunction with the sentient powers), the temporal context of the act of the intellect is retained in the passive intellect. In other words, when one senses an external thing, the sentient powers produce a phantasm from it (which is an intentional sensible form not entirely removed from matter) and the active intellect abstracts the sensible species from it for impression upon the passive intellect. This act of abstraction by the active intellect, together with any further acts of the passive intellect in the intellection of the object are themselves an immaterial object of the intellect that are retained by it.
A7: When we considered the sentient powers of the soul, we identified memory as a distinct power. Is it also true of intellective memory, that it is a distinct power of the soul? Given what we have already seen in the sixth article, we should not be surprised that Aquinas argues that there is no separate power of intellective memory; retention of intelligible species is part of the very definition of the passive intellect. In order to bolster this position he returns to first principles. In order to identify a diversity of powers, one must identify a diversity of objects of those powers; in addition, if the object is specified generally (as for vision), one must not take particular differences (such as black versus white) as specifying diverse powers. The object of the intellect is being in general and it is the passive intellect that becomes the things that it cognizes in receiving the forms of those things in their intentional existence. Although we can identify a distinct active power responsible for the abstraction of intelligible forms from phantasms, there is leeway for further diversification of powers.
A8: So far in this question, we’ve been talking about the intellect and intellective activity. Another word that we frequently use in talking about thinking is reason, the word that lies at the root of identifying humans uniquely as rational animals. Are intellect and reason distinct powers? Aquinas thinks not. To argue his position he recalls that the intellect is concerned with the simple apprehension of intelligible truth; that is, to understand things as they are in their natures. On the other hand, to reason is concerned with proceeding from one set of things that are understood so as to arrive at a new set of things that are understood by using certain processes such as judgement and logical reasoning. He makes analogies comparing the connection between intellect and reason with the connection between movement and coming to rest and possession and coming to acquire. These latter two pairs are each traced back to single powers; it is the same with the intellect and reason. Intellective understanding is like being at rest whereas the process of reasoning is like being in motion; reasoning terminates in new intellectual understanding just as motion terminates in rest. Therefore we should not identify the intellect and reason as separate powers.
A9: It’s not unusual to think of ourselves as sometimes pondering the higher things in life; time, eternity, God, higher mathematics, necessary beings. At other times, we have to turn our attention to lower things: whether I can pay the mortgage this month, which party I should vote for in the election. That we consider some things to be higher and some to be lower might suggest to us that we have a higher reason and a lower reason for thinking about each. Aquinas disagrees and his disagreement shows the importance to him of the unity of how we go about discovering things and thinking about them. If we consider the higher things in life as corresponding to the eternal and the lower things as corresponding to the temporal, then we have to admit that the cognition of each is related to the cognition of the other. When we discover the eternal things in life we go about it by means of the temporal (and Aquinas makes reference here to Romans 1:20). When we think about the temporal, we do it in the context of our knowledge of the eternal.
Aquinas is willing to concede that the way we arrive at the eternal through the temporal and the way we arrive at the temporal from the eternal can belong to different habits, but he insists that they belong to the same power. Now a habit (Latin habitus) as far as Aquinas is concerned is a sort of expertize arrived at through lengthy practice (and we’ll be seeing much more about habits in II-I and II-II of the summa). One has the habit of medicine if one is a good doctor; one has the habit of piano playing if one is an accomplished pianist. Within the intellectual power there are diverse ways of arriving at knowledge. Much of what we have been discussing so far in this treatise concerns the immediate knowledge of apprehension; but other types of knowledge are arrived at through arduous processes of reasoning. These different arduous processes correspond to diverse habits. Arriving at knowledge of the eternal simply involves different habits than those used to arrive at knowledge of the temporal. Similarly, if one identifies (as does the second objection) the higher with the necessary and the lower with the contingent, these still do not call for separate powers but rather for different habits of acquiring knowledge.
A10: Given what we’ve seen already, asking whether intellective understanding is a power distinct from the intellect may seem decidedly odd; intellective understanding simply is the act of the intellect. However, the point of this article is to allow Aquinas to clear up some misunderstandings of terminology that might arise when considering various other authors writing on the subject of the mind.
Aquinas starts off with an interesting linguistic aside comparing how angels are referred to in some books translated from Arabic (presumably Avicenna) compared with some translated from the Greek (presumably Dionysius the Areopagite). But the main point to be made is that although philosophers refer to intellective understanding and to the active intellect, the passive intellect, the habitual intellect and the acquired intellect, there really are only two diverse powers amongst these. The passive intellect can be considered as being in act where it is called intellective understanding or the acquired intellect; this is when it is in the act of intellection of something. It can also be considered when it is in (first) potentiality, ready to have an intelligible species impressed upon it by the active intellect, and then it is simply the passive intellect. Finally in can be considered in the state of first actuality (or second potentiality) where it has received an impressed species but is not actually thinking about it now, where it is called habitual intellect.
The reply to the third objection allows Aquinas to slice the terminology up another way. When the intellect apprehends something, this is called intellective understanding. If it orders what it has apprehended towards the apprehension of something else, this is called intention. Carrying through this process is then called excogitation (or thinking things out). Finally when it combines what it has thought out with some other certain knowledge in an act of judgement, it is said to know or to be wise.
A11: Another way in which one might wish to try and slice up the intellect is into the speculative intellect and the practical intellect. The former is ordered towards truth, the latter towards the good. Put another way, the speculative intellect is that part of the intellect that enables one to know which things are true and which are false, the practical intellect works out what is good and what is not in order that we may or may not take action towards them. In considering whether these are two different powers, Aquinas returns to the principle that one does not diversify powers simply because of an incidental difference in object. That the practical intellect is ordered towards action whereas the speculative is not counts as an incidental difference and therefore they cannot be identified as diverse powers; their objects do not really differ inasmuch as the true and the good can be considered to include one another.
A12: Synderesis is the term used to describe our apprehension of the very first principles of human action. One can find parallels to synderesis in our understanding of the very first principles of reason: the law of the non-contradiction or some form of the law of sufficient reason, for example. When we look at human action, we may think of the opening of Aristotle’s Ethics: “the good has rightly been declared to be that at which all things aim” as pointing towards one of the principles of synderesis. The term itself has a rather obscure historical background: it appear to have been used by Jerome in his commentary on Ezekiel. Unfortunately although Jerome indicates that synderesis is some sort of initial spark of conscience, he doesn’t really differentiate the term clearly from his use of the word conscience (syneidesis in Greek). This has led some to suggest that the term synderesis came about as a result of the error of a copyist of the manuscript! If the term came about as the result of a mistake, it was a happy mistake as it’s the sort of term that philosophy would have to invent if it didn’t exist.
Aquinas asks what this ability to apply the first principles of practical reason is: is it a distinct power of the soul? Aquinas observes that just as we reason on the basis of certain naturally known principles from premises to conclusions in the field of speculative enquiry, so also do we proceed in the field of practical reason. Therefore, just as there are these innate principles that allow us to reason speculatively, so there must also be innate principles that allow us to reason practically. These powers make up a habit (Latin habitus); that is, a sort of expertize in reasoning. In contrast to the types of habit that are learned through extensive practice (such as the habit of medicine and the habit of playing the piano), synderesis is an innate habit bestowed upon us by nature.
A13: In contrast to synderesis, the idea of conscience is much better known; unfortunately it is also widely misunderstood! Conscience is the ability of the practical reason to reach a judgement on the moral worth of a particular concrete action; it is often mistaken for a faculty of the speculative intellect ordered to the assessment of classes of action in general. So, the sort of judgement that the conscience is capable of making is: “was what I did yesterday an act of stealing?” rather than a judgement of the form “is stealing sometimes morally acceptable?”
Following the pattern of the last article, Aquinas asks whether conscience is a distinct power of the soul. Since conscience is knowledge applied to some individual case, it is strictly speaking an act and not a power of the soul. However, we often use the term conscience to refer to the ability to make that application of knowledge to what we do; that is, we confuse the habit of synderesis with the act of conscience.
- The intellect is a power of the soul, which can be divided into a passive part that receives and retains the intelligible species abstracted from the phantasms produced by the sentient intellect; and an active part that is responsible for this process of abstraction.
- We see the action of God as first mover in moving the active intellect to its act of abstraction.
- Aquinas combats a number of contrary positions by insisting that any act of intellection is the act of an experiencing subject; any theory that fails to explain the experiencing I is short of the mark.
- Intellectual memory involves the sentient parts of the soul in remembering the temporal context of events; the reflexive understanding of the act of understanding is directly retained in the passive intellect.
- Reason involves putting to use those intelligible species retained in the passive intellect; it does not constitute a separate power of the intellect.
- When we consider ways of dividing the intellect such as into higher and lower reasoning or into speculative and practical thinking, we do not thereby come across separate powers. These divisions consist in different ways or habits of reasoning within the same power of the intellect.
- Synderesis, which gives us the first principles of practical action, is an innate habit.
- Conscience, by which we make a judgement on the concrete act, is an act.
- If Aquinas’s quotation of Aristotle in the second article, that the intellect is “like a clean tablet on which nothing is written”, seems to us to run counter to modern psychology, we must remember exactly what the two earlier scholars mean by “intellect”. We are well aware these days that animals are born with innate behaviours; but we must also remember that this was perfectly well known in the time of the ancient Greeks as well! Aristotle and Aquinas do not mean that we are born with empty minds and have to learn everything; they mean that we have not had the quiddity of any concrete object impressed upon our passive intellects. Although we would now have to push the boundaries of such learning to before birth, the fundamental point remains.
- The treatment of synderesis and conscience given here may come as a bit of a disappointment. Aquinas gives much greater attention to them in questions 16 and 17 of the Disputed Questions de veritate.