Philo of Alexandria

Wisdom is the art of arts, and although it seems to vary with its materials it must be recognized that its true form never changes. This is evident to those with sharp eyes, but not those who incline to the stuff surrounding [wisdom's] essence, seeing only the character stamped on it by the particular craft. The sculptor Phidias made statues out of bronze, ivory, gold and other materials besides, and in all of these he left the mark of his one same art, by which the craftsman's authorship was recognizable to connoissseur and layman alike. Art, which represents nature, also emulates nature's habit of re-using the same mold, as in the case of twins when it imprints two likenesses differing only in slight details: a perfected art outlines the same forms and fills them in alike no matter how many different materials it takes up. And so its products are siblings, twins and the closest possible kin to one another.

On Drunkenness XXII.88-90

Beintemapoldermolen

Leibniz on perception

One is obliged to confess that perception and what depends on it are inexplicable by mechanical reasons, i.e. in terms of forms and movements. Let's imagine a machine whose structure permits it to think and feel and have perceptions, and go on to enlarge it in our minds, maintaining its proportions, until one could go inside it as into a mill. This being posited, on a visit to its interior one would find nothing but parts pushing against one another, and nothing to explain how perception works. And so it is in the simple substance, and not the composite (i.e. the machine) that we must seek it out. Indeed, perceptions and their alterations are all we find in simple substances. In these alone consist all internal actions of simple substances.

Monadology §17

Stoic roundup

"So much for the Peripatetics. The beliefs of the Stoics remain to be discussed. These men call their criterion of truth 'apprehensive imagination.' Once we have learned what this was to them, and on what points their concepts differ, we will understand what this imagination is.

"According to them, imagination is the striking of an imprint in the soul. On this point they were divided from the outset. Cleanthes took 'imprint' [literally] to mean a combination of ridges and indentations, such as result from the stamp of signet-rings in wax. Chrysippus however found such a notion absurd. To begin with, he says, thinking simultaneously of a triangular figure and a rectangular one would require the imaginative organ to take on different outlines at the same time, simultaneously assuming the shape of a triangle and a rectangle or a circle, which is absurd. Furthermore, when many imaginings arise in us at the same time, the soul would be seized by a multitude of outlines, which is less persuasive still. So he understood Zeno's use of 'imprint' to mean an 'alteration,' rendering the formula: 'Imagination is an alteration in the soul.' The absurdity is removed, if a single organ is to take on a multitude of alterations when many imaginings arise in us at the same time, just like the air: when many people are speaking at the same time it receives untold different blows at once, and sustains many alterations. The ruling element beset by elaborate imaginings will undergo something analogous to this."

"For when we call a man the composite of a soul and a body, or death the separation of soul from body, we are speaking in particular of the [soul's] ruling element. Likewise, whenever we make choices by virtue of their benefits to the soul, the body and its accessories, it is not the entire soul we are reflecting on but its ruling part, to which affections and benefits accrue. And so when Zeno says that 'Imagination is the striking of an imprint in the soul,' we are not to understand not the entire soul but a part of it, and to render the formula as 'Imagination is an alteration of the ruling element.' But even when it's put this way objections remain, for impulse, agreement and apprehension are alterations of the ruling part, and are not the same as imaginations. Whereas imagination is essentially a passive disposition of ours, the former are active faculties. So it's a bad definition, prescribed for too many different cases. It's like when someone defines 'man' by saying 'Man is a rational animal': the meaning of 'man' is unsoundly adumbrated, since a god is also alive and rational. Thus whoever deems imagination to be 'an alteration of the ruling element' goes wrong, since this no more describes it than any of the motions listed here.

"In answer to an objection like this, Stoics revert to 'implications,' saying it is necessary to understand that 'by a passive faculty' is additionally meant. For just as the definition of eros as 'the urge to create a close relationship' implies 'with youths in bloom' (even though this is not stated explicitly, given that no one feels eros for old men past their prime), they say that to define imagination as 'an alteration of the ruling element' implies an alteration resulting from a passive faculty, and not an active one. But not even by these means do their beliefs escape reproach."

Sextus Empiricus, Against Logicians I.227-31, 234-40

Peripatetic roundup

"Seeing that the nature of all things falls into one of two categories (sensible and intelligible, as I was saying), the schools of Aristotle and Theophrastus and the Peripatetics generally acknowledged two criteria for truth: sense for the sensible, and intellect for the intelligible. According to Theophrastus, what is 'manifest' can belong to either category. As a criterion, perception obeys no logic and is not subject to proof, and though it appears prior to intellect in temporal order, intellect has priority over it in terms of its capacity. The sense is stirred by what is sensible, and in the soul of higher animals (such as are capable of movement of their own) another movement is produced from it, in proportion to its clarity with respect to sense. This movement they identify with memory and imagination. Memory is of an affection to the sense, and imagination is of the sensible object which caused the sense to be affected. And so they speak of this kind of movement by analogy to a footprint. Just as the footprint is produced by and from some thing -- by the pressure of a foot, but from some person, let's say Dion -- so too is the above-mentioned movement of the soul produced by some such affection of the sense, and from something quite like the object of sense, to which it retains a certain similarity.

"Furthermore, this movement which can be called memory and imagination includes a third movement after these. This is 'rational imagination,' which is left up to our judgment and follows our choice. This very movement is spoken of as thought, and it is spoken of as mind -- as when for example someone, on encountering Dion, is affected by a sensation and turns away, and by the affection of his sense some image is engendered in his mind (which we earlier called memory, and said it was like a footprint), and from this same image he willfully draws up and fashions a phantásma, such as the category "man." The Peripatetic school of philosophers observe a distinction in this movement of the soul, dividing it into thought and intellect: thought when it is potential, and intellect when it is actualized. For when the soul is capable of fashioning (i.e. is of a nature to do so), it is called thought; and when it is actually engaged in doing so it is called intellect.

"Now from the intellect and thinking arise comprehension, knowledge and art. For thinking is sometimes about individual forms, and sometimes it is about individuals and classes together. The act of making connections between phantásmata of the intellect and gathering individual cases under universal headings is called comprehension, and the final result of all this gathering and classifying are knowledge and art -- knowledge being precise and inerrant, art not so much."

Sextus Empiricus, Against Logicians I.217-24

Jean Pépin on Sentence 16

hai noēseis ouk áneu phantasías
"This is Aristotle's celebrated thesis, more or less as formulated in On the Soul III.7 and again in the short treatise On Memory and Recollection. The passages in question are:
(1) oudépote noeî áneu phantásmatos hē psychē (On the Soul 431a)(2) Tà mèn oûn eídē tò noētikòn en toîs phantásmasi noeî (On the Soul 431b)
(3) noeîn ouk éstin áneu phantásmatos (On Memory 449b-50a)
One could of course mention other passages, among them On the Soul III.8: 'Speculative thought is necessarily applied to some mental image. For mental images are just like objects of sense, except that they are without matter' (432a). Noēmata are not the same as phantásmata, but they cannot exist without them."

"Of the above formulations, (1) and (3) make it clear that the phántasma is necessary for the intellect to function, but they do not say strictly whether it comes first. (2) on the other hand -- 'As for the forms, the intellectual faculty thinks of these in images' -- gives us to understand that phantásmata are not only necessary for operations of the intellect, but exist prior to them."

Commentary in Porphyre / Sentences, ed. by Luc Brisson
(Paris: Vrin, 2005), vol. 2, 447-8

One more from Porphyry

"Intellect is not the first principle of all things, for the intellect is a plurality, and before the many can exist there must exist the One. And the plurality of the intellect is quite clear. The thought on which it dwells is not single but always multiple, and between these thoughts and the intellect there is no difference. So if it is the same as they, and they are many, then the intellect must be a plurality.

"The identity of intellect with the intelligibles may be demonstrated in this way. Anything it contemplates must either be held inside itself or be set in some other medium. The fact of its contemplation is clear, for with thought it comes to be, but the intellect bereft of thought is bereft of its very essence. A theory of contemplation must therefore be sought in the experiences that go with the various kinds of cognition.

"The cognitive faculties assembled inside us are perception, imagination and intellect. Whatever is attended to by means of perception is regarded externally: contemplation is not effected by union with its objects, but takes only an imprint from the encounter with them. No identity between the eye and the thing seen is therefore possible, for if it did not stand apart from its object it could not see. The object of touch would likewise cease to exist if it were brought into identity [with what senses it]. From these examples it is clear that perception and all activities involving perception must be outwardly applied, if any perceptible object is to be apprehended."

"The imagination tends outwardly in much the same way. The image generated through its operations is made to stand outside it, where by these same operations it is received as an externalized image. In this way are objects of sense and imagination apprehended: focused on themselves, these faculties would never hit on a single object, be it perceptible or imperceptible in form.

"The intellect's mode of apprehension is different, for its contemplation is focused and carried out on itself. As an 'eye' fixed on its own activities, if it were to go beyond contemplation of these it would intelligize nothing. Now the intellect's relationship to the intelligible is on the one hand analogous to that of sense and the sensible. But the latter contemplates its object outwardly, deriving the sensible from external matter. Intellect on the other hand concentrates on itself. Otherwise its direction would be outward -- as in the opinion of those who rejected the distinction between imagination and intellect as one of mere nomenclature. For they took intellect to be the imaginative faculty of a rational being. But if matter and the nature of bodies were (as in their view) the basis for all things, and it followed that intellect too depended on these, then whence would our contemplation derive its conceptions of beings, corporeal and otherwise? As abstractions, it is obvious that intellectual entities have no location in material space, and that intellection takes them up only insofar as they are intellectual, uniting them with the intellect and its intelligibles. In processing intelligibles the intellect observes itself; its operations take place through its approach to itself. And since the intelligibles are many -- for the intellect dwells on many things and not one -- it necessarily follows that intellect is a plurality. But prior to the many there is the One, and thus the One is necessarily prior to the intellect."

Sentence 43

Commentaries on Phaedo 66b-d

OLYMPIODORUS THE YOUNGER: "Imagination [phantasía] is a constant impediment to the operations of our intellect.... And so Odysseus needed the moly and straight talk of Hermes to escape the apparition of Kalypso, which obscured his reason as clouds obscure the sun. Not for nothing is she somewhere called "mirage with trailing robes" -- Kalypso was herself a kálymma [a 'covering']. Accordingly, the Kalypso episode was preceded by Odysseus's landing on the island of Kirke, who (as the daughter of the sun) stands for perception.

"Thus does imagination constitute an impediment to our intellect. And when in the grip of a divine visitation we let imagination intrude, the divine energy lapses. For enthusiasm and imagination are directly opposed. And so Epictetus bids us to say within ourselves: 'You are an apparition, and in no way a true appearance' [Encheiridion I.5] -- and [yet] under the influence of imagination the philosophical choir of Stoics understood God to be a corporeal entity. For imagination is what wraps the incorporeal in a body.

"What, then, does [Aristotle] say? 'Without imagination, there is no thought'? But surely, what the soul knows of universals owes nothing to the activity of the imagination."

◊

DAMASCIUS THE SUCCESSOR: "The existence of knowledge without visualization is made plain by our knowledge of such indivisibles as the unit, the point, and the now, and also by our knowledge of universals (for any imprint surely constitutes an individual 'this'). It is also clear from those things that cannot be visualized at all (such as justice and moderation), and from those self-sufficient forms which are demonstrably indivisible and incorporeal, and from the proofs of incorporeal existence generally. This is how to take this passage: not to fall back on perception and imagination as if they led indivisibly to cognition, for these are what Plato shuns.

"How is it that 'We do not think without imagination'? It's that imagination accompanies thought, not as a complement but as a persecutor, the way a storm accompanies the sailor on the sea."

3 Sentences of Porphyry

15. "Memory is not the conservation of mental images, but a putting forth again of what the mind formerly entertained."

16. "The soul contains the reasons for all things, and busies itself with them when called to the task by something else. Either that or it turns to them inwardly, at its own behest. When summoned from without, it tallies sensory perceptions against external facts; when turning inward, it deals with conceptions of the intellect. External perception is not possible without some affection of a living being's sense-organs, and in like manner the operations of the intellect are impossible without imagination. By this analogy, the 'imprint' is accessory to the living sense in the same way that imagination accompanies the soul's intellectual activity."

28. "Containment of the incorporeal within a body cannot be like the beast's enclosure in its den; the body is altogether incapable of encaging or comprehending it in this way. Nor can the incorporeal be contained like air or fluid in a bladder. Rather, it necessarily subsists in its union with outward-tending faculties that direct its descent and implication into a body. In this way does an unspecifiable extension of the incorporeal produce its connection to the body. Nothing binds it but itself, and what liberates it is not the destruction of the body, but its self-guided turn away from sharing the body's sufferings."

Rejected by Plotinus

"Sensations are not imprints nor engravings on the soul. That said, we definitively exclude the persistence of any imprint in the soul by which things learned and felt are retained as memories, when no such print is made in the first place. The notion that a trace is produced in the soul depends on the same thesis as its persistence as memory: to reject one is to reject the other. We who reject both are obliged to discover their true workings, since we dispute that sensation is an imprint produced in or on the soul, and that memory is a matter of the imprint's persistence.

"The conclusions we reach by examining our brightest sense will apply to the other four as a matter of course. In all cases of seeing, it is clear that we focus our gaze on the object of sight in the place where it is directly exposed to us, and that the resulting cognitive event take place there, exterior to the seeing soul. There being no blow produced within the soul, I daresay it takes no mark from any such blow (as wax does from a signet-ring) when it sees. Nor would it be necessary to look out at anything, if the soul already contained the form of the thing beheld, and looked on its stamp as something pressed therein.... Semblances and shadows of the visible would be all that we saw, and the visible and the real would be two distinct orders."

"So how does it work, if not like this? Perception is not the vessel of what it relates, for it is not a passive faculty but a dynamic one which acts on whatever is ordained for it. Thus it is that the soul is capable of discriminating between the visible and the audible, which I do not believe would be possible if both were imprints. Perceptions are not passive impressions, but active engagements of what the senses comprehend. Accustomed as we are to believing that the senses know nothing until they are struck, we mistake sensation for a passive event, and think the senses mastered by what they in fact master."

Ennead IV.6.1-2

Greek seals

From Intaglios and Rings by John Boardman (Thames & Hudson, 1975).

Gorgon's head, 8 x 16 x 12mm, ca. 500 BCE.

Crouching lioness, 8 x 18 x 8mm, late 5th c. BCE.

Carrier pigeon, 7 x 14 x 11mm, mid 5th c. BCE.

And again

"To what part of the soul, then, does memory belong? The answer is clear: to the same part as the imagination. The essential objects of memory [i.e. sensory perceptions] are the fabric of the imagination, and without imagination its accidental objects [i.e. thoughts] would not occur.

"Someone may be puzzled: if affection is present to the mind, and the real-life thing is excluded, then how is anything remembered in its absence? For it is clear that what is thus produced through sense perception in the soul and its affiliated region in the body must be thought of as some kind of still-life [zōgráphēma], and the fact of having it we call memory: as it occurs, the movement leaves something like an imprint of the perception as its sign, as people do when using signet-rings to make a seal."

"But if this truly describes the events of memory, which is it that we remember: the affection, or that thing from which it was produced? If it is the former, we would be unable to remember anything in its absence. And if it is the latter, given that what we sense is the affection, [the same question arises:] how do we remember the absent thing which we do not presently sense? And if something similar to an imprint or an inscription is inside us, how is our perception of it equal to the memory of something else, and not the selfsame thing? For when memory is actualized, what one contemplates and perceives is this affection.

"So how will one remember a thing when it is not there? One might as well be able to see and hear what is not there. Is this what in fact happens, and how it is received? For even as a picture painted on a panel is both a picture and a portrayal, and being one and the same thing is nevertheless endowed with different sorts of being, and it is possible to regard it both as a picture [unto itself] and a likeness [of something else] -- even so, we must apprehend our interior phántasma as an image with being unto itself, as well as being the image of something else. Insofar as it is unto itself, it is an object of contemplation and a mental image. Inso far as it is of something else, it is a likeness and a memory."

On Memory and Recollection 450a22-32, 450b11-27

Aristotle on the same

"On the subject of perception in its totality, we must understand it as what receives the forms of things sensed in isolation from their matter, the way wax receives the device [sēmeîon] of a signet-ring in isolation from its iron or silver: the iron or silver device is taken in, but not the iron or silver as such. Similarly, the senses are in every case affected by a thing's color, taste or noise -- not that which a thing is said to be, but qualities which it has and are accounted for."

"If thinking is indeed comparable to perception, it is either an affection caused by what is thinkable or something of the kind. Though thought itself is unaffected, it must be receptive of its object's form, and able to be like it while remaining something else. As the sensory faculty is to the object of sense, so must mind be to the thinkable. Now since the mind thinks all things, in order to exercise its force -- that is, to know -- it must as Anaxagoras says be 'unmixed' (59B12 DK), for any foreign object that comes in from outside hinders and obstructs it. Thus the mind can have no nature but a potential one. So that part of the soul called 'mind' (with which the soul does its thinking and conceiving) has no actual existence until it thinks. For this reason it cannot rightly be said to mix with the body either. For then it would take on qualities like hot or cold, or it would reside in an organ as do the senses. But it has none. It is not wrong to call the soul a place of forms, as long as this is restricted to its thinking capacity, and the forms are understood to be potential and not actual.

"The senses and the mind are dissimilar in their imperviousness to affection. On considering the sensory organs and sensation this is easy to see, for after an intense sensation the sense is rendered inoperative -- as with the sense of hearing after a loud sound, or the inability to see or smell in the wake of strong colors and aromas. But the mind that thinks an intense thought finds that lesser thoughts are heightened, not diminished."

On the Soul II.12, III.4

The well-known simile

SOCRATES: Do my account the favor of supposing that our souls contain a slab of wax. This slab varies in size, purity and hardness from individual to individual, and in some cases its consistency is ideal.
THEAETETUS: So I shall suppose.
SOCRATES: Let us go on to say it is a gift from Mnemosyne, mother of the Muses, and that it works like this: of all we see or hear or think of on our own, we lay the slab beneath those thoughts and perceptions we wish to remember and create an impression, just like the seals we stamp with signet-rings. Whatever is imprinted, we hold in our memory and our knowledge as long as its image holds, but what is washed away or is impossible to imprint becomes forgotten and unknown.
     ....Knowing you and Theodorus, I retain in that waxiness signs for both of you, as if left by signet-rings. Now when from far off I get an indistinct view of you together, I strive to tally a particular sign against a particular sight, and to make it fit the trace of its own imprint. But in my rush I fumble my attempt at recognition, and match the sight of one to the other's sign, as when people bind their sandals to the wrong feet. You could also compare it to what happens in a mirror, when right and left trade places and confound the sight. By this type of error, judgment is parted from the truth and rendered false.
THEAETETUS: A very likely account, Socrates, and a marvelous description of what can happen to our judgment.
SOCRATES: Besides this there occurs the case where, knowing you both, I perceive one of you but not the other, and my knowledge of the other is not in accordance with my perception of him. When I described it like this previously you did not understand me.
THEAETETUS: I sure didn't.
SOCRATES: Earlier [at 192b], I was saying that one man who knows another and perceives him and holds his knowledge of him in accordance with his perception would never confuse him with a third man he knows and perceives, as long as his knowledge of the third man was also held in accordance with his perception. Was that not it?
THEAETETUS: Yes.
SOCRATES: Now I'm talking about about what went missing from that account. It's the case in which we say false opinion arises: when, knowing two men and seeing them both (or perceiving them by some other means), we fail to hold the sign of each in accordance with the perception, and like a poor archer straying from the target we get it wrong. And this is what we call falsity.
THEAETETUS: Quite fairly.
SOCRATES: So any time a sign is met by its corresponding perception but another sign corresponding to an absent perception gets fastened to it, thought is deceived. By this account (if what we are saying is correct), it is impossible to be deceived or judge falsely about things unknown and never perceived. Rather, it is about the things we know and perceive that judgment turns and darts in its alternation between falsity and truth: true when it aligns the proper stamps precisely with what made them, and false when it gets them crooked and aslant.

Theaetetus 191c-e, 193c-194b