In Kantian philosophy, a transcendental schema (plural: schemata; from Ancient Greek: σχῆμα, 'form, shape, figure') is the procedural rule by which a category or pure, non-empirical concept is associated with a sense impression.
Kant's a priori concepts, on the other hand, are alleged to have sense when they are derived from a non–experienced mental schema, trace, outline, sketch, monogram,[13] or minimal image.
"[21] These examples ensure that "our abstract thinking has not strayed far from the safe ground of perception, and has possibly become somewhat high-flown or even a mere idle display of words.
"[21] In the same way that examples provide signification for empirical concepts, schemata help to answer the question of "whether operating with the categories is anything other than playing with words.
In this way, Beck showed that a transcendental schema is the rule that leads to the understanding of successive [in time] sensations according to various pure concepts [Kant's "categories"].
"[27] Metaphysical entities that are not related to time, such as spontaneous or uncaused movements, immortal souls, and eternal gods, are products of unschematized categories.
To make sense of such ideas [of reason] we must accordingly have recourse to an alternative procedure, in which use is made of ‘symbols’ as opposed to schemata proper.
What happens here is, roughly, that we find some empirically intuitable situation which can serve as a model by reference to which the idea [of reason] can be made comprehensible.
[23] Kant claimed that time is the only proper and appropriate transcendental schema because it shares the a priori category's generality and purity as well as any a posteriori phenomenon's manner of appearance.
"This suggests that he may have thought at one point of recasting the Schematism argument in a fundamental way, by substituting space for time; but if he had this idea, he did not carry it out.
Norman Kemp Smith claimed that there is apparently no good reason why Kant did not consider space to also be a transcendental schema for his Categories.
"Possibly Kant’s very natural preoccupation with his new revolutionary doctrine of inner sense and productive imagination has something to do with the matter [i.e., is the reason for his elimination of space].
[79] Kant, according to Professor Ewing, for one category did use space as a transcendental schema to unify a pure concept with a sensible intuition.
[81] Werner Pluhar explained why time, rather than space, is used as a connection to include (subsume) sensory intuition in the Kantian categories or pure concepts of the understanding.
It is a minimal outline, monogram, or diagram that realizes or executes an abstract, general concept or idea (Idee) as actual, perceptual experience.
Walsh, of the University of Edinburgh, wrote: "The chapter on Schematism probably presents more difficulties to the uncommitted but sympathetic reader than any other part of the Critique of Pure Reason.
"[87] Schopenhauer's notebooks contained entries that described Kant's chapter on schemata as "an audacious piece of nonsense"[88] and the schema as "an absurdity whose non–existence is plain.
Schopenhauer also alleged that schemata were introduced merely to give plausibility to Kant's description of the categories or pure concepts of the understanding.
"[92] The Scottish philosopher Robert Adamson wrote: "Kant's manner of explaining the functions of schematism is extremely apt to be misunderstood, and to mislead.
"[107] The enormous importance of the concept of the transcendental schema was emphasized by Peirce when he wrote that "if the schemata had been considered early enough, they would have overgrown his whole work.
"In the first Critique, Kant introduces the [transcendental] schema by arguing that it is needed to mediate between the pure concepts of the understanding and imagination (intuition).
In fact, it is not only the foundation of the whole Kantian philosophy, and the type according to which its symmetry is carried through everywhere…but it has also really become the Procrustean bed on to which Kant forces every possible consideration…."
[117] "[E]ven a reader as acute and sophisticated as Jacob Sigismund Beck wrote to Kant in [3 July] 1792 to express his puzzlement over the Typic.
For example, Plato wrote about an endless series or infinite regress of Forms (i.e., Ideals, Ideas, Paradigms); Aristotle deliberated upon the Third Man Argument.
"[129] Kant's abstract analysis of perceptual knowledge was, according to Adamson, the misleading separation of an organic unity into individual components.
Canadian professor John Watson, in his discussion of Kantian philosophy, wrote about supposed supersensible, atemporal beings such as God or the soul.
[133] Accordingly, timeless "...supersensible realities...are not capable of being 'schematized,' do not admit of the application to them of the [Kantian] categories and can never become objects of actual sensible experience.
[136] The philosopher Mark Johnson discusses Kant's conception of a schema with respect to developing a theory of the imagination within cognitive science.
In an increase of ambiguity and confusion, some cognitive scientists today have appropriated the often–misused technical term "schema" to mean Kantian Category.
…here more than anywhere else do the intentional nature of Kant's method of procedure and the resolve, arrived at beforehand, to find what would correspond to the analogy, and what might assist the architectonic symmetry, clearly come to light.