Human Beings Acquire Reason

Aristotle thought that over time human beings naturally acquire (the kind of cognition he calls) "reason" and that this process is an instance of teleological causation (change for the sake of an end). The end is the existence the unmovable first mover enjoys. The presence of reason makes human existence like the divine existence of the unmovable first mover.

The process in which human beings acquire reason is "induction" (ἐπαγωγή). The process of induction begins with perception. Memory comes next. After memory, comes "experience." After experience, comes reason and the "knowledge" that belongs to reason. It follows that reason is not present in human beings from birth. It comes to be present as they mature.

The relationship between "experience" and "reason" in induction is enabling, not evidential. Aristotle thinks that this experience enables a human being to have reason and knowledge that belongs to reason This experience does not provide evidence for this "knowledge." A human being does not infer this knowledge from this experience. Inference is an ability of reason.


The Process of Induction

"All animals have an inborn discriminatory capacity, called perception. If perception is present, in some retention of the percept comes about, but in others not. ... When many such things come about, a difference comes about, so that some come to have reason (λόγον) from the retention of such things, and others not. From perception comes memory, and from memory (when it occurs often in connection with the same thing), experience (ἐμπειρία); for memories that are many in number from a single experience. From experience, or from the whole universal (καθόλου) that has come to rest in the soul (the one apart from the many, whatever is one and the same in all those things), there comes a starting-point of art (τέχνης) and of knowledge (ἐπιστήμης), of art if it deals with coming to be, of knowledge if it deals with being. Thus the states [that grasp the starting-points for demonstration] neither belong in us in a determinate form, nor come about from other states that are more cognitive (γνωστικωτέρων); but they come about from perception—as in a battle when a rout occurs, if one man makes a stand another does and then another, until a position of strength is reached. The soul is such as to be capable of undergoing this. ... [Thus it] is clear that it is necessary to cognize (γνωρίζειν) the primary things by induction (ἐπαγωγῆι)." (Posterior Analytics II.19.99b-100b).

"Animals are by nature born with the power of sensation, and from this some acquire the faculty of memory, whereas others do not. ... The other animals live by impressions (φαντασίαις) and memories, and have but a small share of experience (ἐμπειρίας); but the human race lives also by art and reasoning (τέχνῃ καὶ λογισμοῖς). It is from memory that men acquire experience, because the numerous memories of the same thing eventually produce the effect of a single experience. Experience seems very similar to science and art, but actually it is through experience that men acquire knowledge and art (ἐπιστήμῃ καὶ τέχνῃ). ... Art is produced when from many notions (ἐννοημάτων) of experience a single universal (καθόλου) judgment is formed with regard to like objects. To have a judgement that when Callias was suffering from this or that disease this or that benefited him, and similarly with Socrates and various other individuals, is a matter of experience; but to judge that it benefits all persons of a certain type, considered as a class, who suffer from this or that disease (e.g. the phlegmatic or bilious when suffering from burning fever) is a matter of art" (Metaphysics I.980a-981a).

"Experience" (ἐμπειρία)

In the Metaphysics, Aristotle appeals to medicine for an example to distinguish "experience" (ἐμπειρία) from "art" (τέχνη) and "knowledge" (ἐπιστήμη).

The example contrasts the judgments of the medical practitioner and the medical theorist. The practitioner can make the "judgment that when Callias was ill of this disease this did him good, and similarly in the case of Socrates and in many individual cases." This "judgment" (ὑπόληψιν, I.1.981.a7) is a matter of "experience" (ἐμπειρίας, I.1.981a9). The medical theorist can make the judgment "that a given thing has done good to all persons of a certain constitution, marked off in one class, when they were ill of this disease, e.g., to phlegmatic or bilious people when burning with fever." This judgment is a matter "knowledge and proficiency" (τό γε εἰδέναι καὶ τὸ ἐπαΐειν, I.1.981a24). "Experience" gives the practitioner the ability to make the correct diagnosis in circumstances in which the layman is more likely to make a mistake, but "experience" is not the same as "art" (τέχνη) or "knowledge" (ἐπιστήμη). Aristotle says that "men of experience ... know that the thing is so, but do not know the why, while the others know the why and the cause" (οἱ μὲν γὰρ ἔμπειροι τὸ ὅτι μὲν ἴσασι, διότι δ᾽ οὐκ ἴσασιν: οἱ δὲ τὸ διότι καὶ τὴν αἰτίαν γνωρίζουσιν, I.1.981a28-30).

Aristotle's view is that "knowledge" (ἐπιστήμη) as an achievement of reason. In this way, his conception is similar to the conception of belief Plato has Socrates articulate in Theaetetus 184b-187a. There the suggestion is that to form the belief that a given thing is F, it is necessary to have more than experience because to form the belief requires one to grasp what it is for something to be F.

  "Knowledge (ἐπιστήμη) is not in the sensations (παθήμασιν), but in the process of reasoning (συλλογισμῷ) about them; for it is possible, apparently, to apprehend being and truth by reasoning, but not by sensation.
  So it seems, Socrates.
  Then will you call the two by the same name, when there are so great differences between them?
  No, that would certainly not be right.
  What name will you give, then, to the one which includes seeing, hearing, smelling, being cold, and being hot?
  Perceiving. What other name can I give it?
  Collectively you call it, then, perception (αἴσθησιν)?
  Of course.
  By which, we say, we are quite unable to apprehend truth, since we cannot apprehend being, either.
  No; certainly not.
  Nor knowledge either, then.
  No.
  Then, Theaetetus, perception and knowledge could never be the same.
  Evidently not, Socrates; and indeed now at last it has been made perfectly clear that knowledge is something different from perception.
  But surely we did not begin our conversation in order to find out what knowledge is not, but what it is. However, we have progressed so far, at least, as not to seek for knowledge in perception at all, but in some function of the soul, whatever name is given to it when it alone and by itself is engaged directly with realities.
  That, Socrates, is, I suppose, called having opinion.
  You suppose rightly, my friend" (Theaetetus 186d-187a).


The medical practitioner is a special case "experience" (ἐμπειρία)

Although Aristotle uses the example of the medical practitioner to distinguish "experience" (ἐμπειρία) and "knowledge" (ἐπιστήμη), the ability that characterizes the medical practitioner is a special case of "experience." The medical practitioner grasps empirical generalizations about diseases and their proper treatments. This grasp is the result of long and careful observation, but "experience" is not always a matter of this kind of observation. Human beings can reliably discriminate human beings from the other things they encounter in their lives. Aristotle does not say so explicitly, but it is natural to suppose that he thinks that "knowledge" (ἐπιστήμη) of what a human being is is not necessary for this ability and that for most human beings this ability is a matter of "experience" (ἐμπειρία).

(Aristotle's view is that the practitioner does not have "knowledge" (ἐπιστήμη). As Aristotle understands it, the cognition that characterizes the practitioner is a matter of perception and memory. Aristotle describes it a matter "habit" (ἔθος, I.1.981b5), not "reason." He does say that practitioners "know (ἴσασι) that the thing is so," but here he is talking about this cognitive state in the way it is ordinarily talked about. Because the cognitive state that characterizes the practitioner does not belong to reason, it follows for Aristotle that this cognitive state is not "knowledge" (ἐπιστήμη).)


Some purposeful behavior is a matter of "experience" (ἐμπειρία)

In the Metaphysics at I.1.980b, Aristotle says that some animals are "sensible" (φρόνιμα). These animals are capable of controlling their behavior by discriminating among things in their environment in ways that benefit themselves, but this behavior is not an exercise of "reason." Whereas "the other animals live by appearances and memory, and have [comparatively] little experience, human beings also live by art and reasoning" (τὰ μὲν οὖν ἄλλα ταῖς φαντασίαις ζῇ καὶ ταῖς μνήμαις, ἐμπειρίας δὲ μετέχει μικρόν: τὸ δὲ τῶν ἀνθρώπων γένος καὶ τέχνῃ καὶ λογισμοῖς, I.1.980b25-28). The purposeful behavior that is an exercise of "reason" is a matter of "choice" (προαἱρεσις), but for Aristotle not all purposeful behavior in human beings is a matter of "choice."

Choice "is not present in other animals, nor at every time of life, nor in a human being no matter what state he is in; for deliberation (βουλεύσασθαι) is not, either, nor a judgment about the why (ὑπόληψις τοῦ διὰ τί); a belief (δοξάσαι) about whether something should be done or not may well be present in many, though not through reasoning (λογισμοῦ)" (Eudemian Ethics II.10.1226b21-25).

"For that part of the soul is deliberative which is capable of discerning (θεωρητικὸν) a cause (αἰτίας): the for sake of which (ἕνεκα)—which is one of the causes—‘cause’ being something because-of-which. And we say that the for sake of which something is or comes to be is a cause—for instance, the carrying of goods is a cause of walking if it is for the sake of that that a man walks. That is why those who have no goal before them are not in a position to deliberate" (Eudemian Ethics II.10.1226b25-30).


Reason Grasps Universals

Aristotle thinks that it is distinctive of reason to grasp universals. "[E]xperience is knowledge of particulars, but art is knowledge of universals (ἐμπειρία τῶν καθ᾽ ἕκαστόν ἐστι γνῶσις ἡ δὲ τέχνη τῶν καθόλου)" (I.1.981a16; cf. I.1.981a21). The man of experience does not have cognition of the universal. He does not grasp the "form" (εἶδος, I.1.981a10) that the doctor with art (the medical theorist) knows is common to the patients who have a certain disease and benefit from a certain treatment. The doctor with experience (the medical practitioner) discriminates the disease in his patients in terms of how they look. This ability is an exercise of experience. It is a matter of perception and memory, not reason. The medical practitioner does not conceive of the disease in terms of a universal, being phlegmatic or bilious or having a burning fever. Because he does not grasp the universal, he does not understand what the disease is and why the treatment is successful for this disease.

The point is not that the doctor with experience has less clinical success than the doctor with the art. Aristotle himself explicitly says otherwise (I.1.981a12-13). It is possible for the practitioner to have the experience that allows him to discriminate all and only the patients who have a certain disease that will benefit from a certain treatment. Still, the practitioner does not grasp "the why and the cause (τὸ διότι καὶ τὴν αἰτίαν)" (I.1.981a30). This grasp is an achievement of reason. Without this grasp, there is no "knowledge" (ἐπιστήμη). Knowledge requires that the knower be in a special position with respect to the proposition he knows. Sometimes this point is expressed by saying that knowledge requires justification, but for Aristotle what one might ordinarily accept as justification in such cases is insufficient. The doctor with experience might be able to point to the success he has had in treating patients whose disease he identifies in terms of a certain way they all look, but Aristotle thinks that for "knowledge" (ἐπιστήμη) it is necessary to grasp the universal and intelligible features that underlie the sensible and figure in the account of what the disease is and why the treatment is successful.

"From experience (ἐμπειρίας), or the universal (καθόλου) that has come to rest as a whole (παντὸς) in the soul (the one apart from the many, whatever is one and the same in all those things), there comes a starting-point of art (τέχνης) and of knowledge (ἐπιστήμης), of art if it deals with coming to be, of knowledge if it deals with being" (Posterior Analytics II.19.100a).

"Art is produced when from many notions of experience (ἐμπειρίας ἐννοημάτων) a single universal (καθόλου) judgment is formed with regard to like objects" (Metaphysics I.981a).


Knowledge that belongs to Reason

The battle metaphor Aristotle uses in II.19 of the Posterior Analytics is not easy to interpret, but it suggests that Aristotle supposes that "reason" does not grasp universals one by one in isolation and thus that this grasp does not take place without the advent of "knowledge" (ἐπιστήμη) and thus the possession of demonstrations that exhibit necessary connections between universals.

If this is right, then presumably Aristotle also thinks that the reason human beings first acquire is something that can be improved and perfected. A human being first grasps universals in some domain and somehow comes to deduce that certain further relations hold and thus in this way extends his knowledge and understanding of the domain.


Aristotle is Platonist and Platonic critic

Aristotle works out his understanding of how human beings acquire reason against the background of Plato's Theory of Recollection. Aristotle thinks that Plato was right in one way but wrong in another about reason in the human soul. Aristotle does not think the soul and reason can exist independently of the body, he conceives of reason in terms of the possession of certain concepts and the knowledge that constitutes the possession of these concepts. In this way, Aristotle rejects the ontological thesis but accepts the epistemological thesis in the Theory of Recollection.

  "We say there is such a thing as equality (ἴσον). I do not mean one piece of wood equal to another, or one stone to another, or anything of that sort, but something beyond that--the equal itself (αὐτὸ τὸ ἴσον). Shall we say there is such a thing, or not?
  We shall say that there is most decidedly Socrates.
  And do we know what it is?
  Certainly.
  Whence did we come upon the knowledge of it? Was it not from the things we were just speaking of, by seeing equal pieces of wood or stones or other things, on the occasion of them that equal was in thought (ἐνενοήσαμεν), it being different from them? ... It is on the occasion of those equals, different as they are from that equal, that you have thought and come upon knowledge (ἐπιστήμην) of it?
  That is perfectly true (Phaedo 74a-c).

  "Then before we began to see or hear or use the other senses we must somewhere have gained a knowledge of the equal itself, if we were to compare with it the equals which we perceive by the senses, and see that all such things yearn to be like the equal itself but fall short of it.
  That follows necessarily from what we have said before, Socrates.
  And we saw and heard and had the other senses as soon as we were born?
  Certainly.
  But, we say, we must have acquired a knowledge of equality before we had these senses?
  Yes.
  Then it appears that we must have acquired it before we were born.
  It does.   Now if we had acquired that knowledge before we were born, and were born with it, we knew before we were born and at the moment of birth not only the equal and the greater and the less, but all thing such as these? For our present argument is no more concerned with the equal than with the beautiful itself and the good and the just and the holy, and, in short, with all those things which we stamp with the what it is itself (τὸ ‘αὐτὸ ὃ ἔστι’) in our dialectic process of questions and answers; so that we must necessarily have acquired knowledge of all these before our birth.
  That is true, Socrates" (Phaedo 75b-d).





Perseus Digital Library:
Plato, Phaedo, Theaetetus
Aristotle, Eudemian Ethics, Metaphysics.
Henry George Liddell, Robert Scott, A Greek-English Lexicon:
γνωρίζω, gnōrizō, verb, "gain knowledge of, become acquainted with, discover,"
ἐμπειρία, empeiria, noun, "experience,"
ἐννοέω, verb, "reflect upon, consider,"
ἐννοηματικός, ennoēmatikos, adjective, "notional,"
ἔννοια, noun, "notion, conception,"
ἐπαγωγή, (from ἐπᾰ́γω = ἐπι +‎ ἄγω),
καθόλου, (= καθ᾽ ὅλου), katholou, adverb, "on the whole, in general"
λογισμός, logismos , noun, "counting, calculation,"
συλλογισμός, syllogismos, noun, "computation, calculation,"
τέχνη, technē, noun, "art"

Arizona State University Library:
Loeb Classical Library:
Posterior Analytics


"To say that it is somehow a natural process by means of which we arrive at first principles is to exploit Aristotle's generous conception of what is natural and to focus on just one aspect of it. This becomes particularly clear if we keep in mind that on Aristotle's view it also is the case that by nature we are meant to be virtuous and are thus constructed as to naturally be virtuous. Nevertheless, Aristotle also assumes that it takes a great deal of effort on our part to come to know the first principles in general (and thus to become wise), or even just the first principles in some domain. What is needed for this is a great deal of often highly specialized observation and of often highly technical reflections. But this should not obscure the fact that the insight, if it is an insight, does not derive its epistemic status from these observations and reflections which lead up to it. What makes it an insight is not the support it gets from observations or considerations, but that one finally sees in a way which fits how the features in question are related to each other and to other relevant features" (Michael Frede, "Aristotle's Rationalism," 172. Rationality in Greek Thought, edited by Michael Frede and Gisela Striker (Oxford University Press, 1996), 157-173).

"[Aristotle thinks] that organisms have to be understood teleologically, as naturally tending to achieve full development and perfection in their kind, unless handicapped or their development is thwarted. Since we naturally do have reason and since reason functions best, and serves its function best, if we do have the requisite knowledge, he assumes that we must be constructed in such a way as to be able to acquire the knowledge reason needs to function well. And he, too, thinks that he can explain this by assuming that there is a process which leads, on the basis of perception and memory, not only to our having concepts, but to our having concepts which are adequate to the way things essentially are, and which thus provide us with basic knowledge about things, but also with the ability to think and reason about things, properly speaking, instead of, for instance, just having impressions or even generalized impressions of things" (Michael Frede, "Introduction, 14. Rationality in Greek Thought, edited by Michael Frede and Gisela Striker (Oxford University Press, 1996), 1-28). "On Aristotle's view it does not seem to suffice for thinking that we have a notion of, say, a human being which allows us, by and large, to distinguish successfully between human beings and other things; the notion rather has to be based on a sufficient grasp of what it is to be a human being, of the crucial feature or features of human beings, and of how these features are related to each other and to a whole network of features. ... To grasp what it is to be a human being, on Aristotle's view, is more than just to grasp what human beings have in common; it is to grasp something which figures prominently in the explanation of human beings and their behavior" (Michael Frede, "Aristotle's Rationalism," 164. Rationality in Greek Thought, edited by Michael Frede and Gisela Striker (Oxford University Press, 1996), 157-173).

"Aristotle in [Posterior Analytics] B 19 not only claims that we only come to have reason, only come to be, at least ideally, thus disposed to know first principles, he also explains how this disposition arises out of perception and experiences. ... However obscure, and in their interpretation controversial, the details of his account of how we acquire concepts may be, it is abundantly clear from 100a12-13 that Aristotle does not envisage that the concepts are acquired one by one in isolation. However we interpret the battle metaphor, it seems clear that he assumes that we begin with a tentative and unstable grasp of the different features, which constantly threatens to collapse until we get a firm grasp on some feature such that, given the way the features are interrelated, our grasp of the whole group solidifies and stabilizes. This is also why Aristotle can assume that having the right concepts is to know first principles. We do not come to acquire these concepts piecemeal, but by a process of mutual adjustment with other related concepts, as a result of which certain elementary relations between features in the end seem evident. Again it is clear that Aristotle, to explain how we first come to grasp universals, does not appeal to some mysterious power of the mind to see directly or intuit features or forms, but to some complex process in the course of which our notions again and again are readjusted until they finally fit into a coherent and appropriately structured system of notions and corresponding beliefs in terms of which we finally can make sense of what know from experience" (Michael Frede, "Aristotle's Rationalism," 171. Rationality in Greek Thought, edited by Michael Frede and Gisela Striker (Oxford University Press, 1996), 157-173).