In the glossary to his translation of Aristotle’s On the Soul, Joe Sachs nicely summarizes the various roles of phantasia or “imagination” in Aristotle:

“A power of the soul that perceives appearances when perceptible things are absent and thinks without distinguishing universals (429a 4-8, 434a 5-11). The imagination is identified in On Memory and Recollection as the primary perceptive power of the soul (449b 31 – 450a 15). Thus, many activities discovered in On the Soul may be collected and attributed to the imagination, such as perceiving common and incidental objects of the senses, being aware that we are perceiving, discriminating among the objects of the different senses (425a 14 – b 25), distinguishing flesh or water (429b 10-18), and perceiving time (433b 7). Also, implicit within the power of imagination to behold images (phantasmata), there must be imagination in a second sense, eikasia, by which we can see an image as an image (eikon) or likeness (On Memory and Recollection 450b 12-27)” (pp. 194-195; citations in original).

In the above, I would particularly highlight “thinking without distinguishing universals” and “being aware that we are perceiving”. Imagination — and not intellect, for instance — seems to me to be the primary source suggested in Aristotle for what we, following Locke, call “consciousness”. Also noteworthy is language suggestive of what Kant would later call synthesis.

The vital implication here is that the closest analogue of “consciousness” in Aristotle comes into being not as a transparent medium of representation, but rather as a shifting collection of concrete forms in imagination. Further, the forms we experience are not just passively received, but actively organized and discriminated at a pre-conscious level. Thus when Aristotle says — as he also does — that, e.g., the eye is essentially passive in receiving forms as differentiations in received light — this latter is intended at a purely physical level, and is far from providing a full account of, e.g., visual perception by a human.

Prior to Descartes’ confabulation of scholastic “cogitation” and “intellection”, concrete human psychic activity or “cogitation” was generally recognized as having its roots in imagination. Intellection was understood to have a more specialized role, focused on the constitution of universals. However, attempts to reconcile Aristotle with Plotinus and Proclus in the Arabic tradition, and then with Augustine and pseudo-Dionysius in the Latin tradition, provided a background that was ultimately very supportive toward Aquinas’ strong claim that intellect must after all be understood as the leading part of the individual human soul, morally responsible for all its concrete thoughts and actions. This made it far more plausible for Descartes to take the further step — which Locke followed — of simply identifying cogitation and intellection. The self-transparency of the cogito in Descartes and of consciousness in Locke, respectively — along with their identification with intellection — served to marginalize the role of forms in imagination in their conceptions of “mind”.

A very important feature of Kant’s work that is relatively little appreciated is that he restored a central role for “imagination” in philosophical psychology and anthropology. For Kant, humans can have neither direct knowledge of empirical facts or objects, nor any knowledge of transcendent realities. All intellection and knowledge are discursive, as I think Aristotle would have agreed. We have immediate though “blind” intuition of a sensible manifold, but intellectual intuition is an oxymoron, because intellection is inherently discursive. And in between the synthesis of initial sensory apprehension in intuition and the synthesis of recognition in the concept (Kant’s equivalent for intellection) comes a crucial synthesis of reproduction in imagination. Though his terminology is quite different, Kant not only recovers but even expands upon the role that imagination played in Aristotle.

In Kant and the Capacity to Judge, Beatrice Longuenesse carefully develops what Kant says about imagination in the Critique of Pure Reason. This is a major dimension of her book, so I can only give a flavor of it here.

“The imagination ‘in which’ there is reproduction is not the imagination as a faculty or power (Einbildungskraft), but the representation produced by this faculty (Einbildung)” (p. 35). Though Kant uses the terminology of representation, this effectively refers to the same forms in imagination that Aristotle emphasized.

“[Kant] shows that these acts of combination can contribute to the cognition of a phaenomenon, an object distinct from the ‘indeterminate object of empirical intuition’ (Erscheinung [or mere appearance]), only if they all belong to one and the same act of synthesis of the spatiotemporal manifold. The form of this act is determined a priori by the nature of our mind, and its outcome is threefold: the manifold of intuition represented ‘as’ manifold, the representation of imagination (Einbildung) emerging from empirical associations, and finally the universal representation or concept, under which particular representations are subsumed. This act is that very act of synthesis which Kant, in section 10, attributes to the imagination, in the A Deduction [of the categories] more precisely to transcendental imagination, and which in the B Deduction he calls synthesis speciosa, figurative synthesis” (pp. 35-36).

As usual in Kant, “transcendental” means not metaphysical, but simply constitutive in a way that is not reducible to empirical events. Longuenesse points out that imagination in Kant is not merely reproductive, but also productive. In any case, for Kant not only the logical “matter” but also the elaborated form of our fully constituted experience owes a great deal to imagination, and a recognition of this — as opposed to the assumption of a putative transparency of consciousness — is fundamental to the “Critical” attitude Kant aimed to promote. Here I am using “form” in a sense more Aristotelian than Kantian. (See also Capacity to Judge; Figurative Synthesis; Imagination, Emotion, Opinion; Animal Imagination; Imagination; Four Layers of Being Human.)