Leibnitz, by way of distinction from unconscious perception, gave the name " apperception " to consciousness.
Wundt, in consequence, thinking with Kant that apperception is a spontaneous activity, and with Fichte that this activity requires will, and indeed that all activity is will, infers that apperception is inner will.
According to him, then, attention, even involuntary attention, requires inner will; and all the functions imputed by Hume to association, as well as those imputed to understanding by Kant, require apperception, and therefore inner will.
But he also recognizes association by similarity, or assimilation, or " apperception " in Herbart's more confined sense of the word, and association by contiguity, or complication.
If knowledge is experience of ideas distinguished by inner will of apperception into subject and object in inseparable connexion, if the starting-point is ideas, if judgment is analysis of an aggregate idea, if inference is a mediate reference of the members of an aggregate of ideas to one another, then, as Wundt says, all we can know, and all reason can logically infer from such data, is in our ideas, and consciousness without an object of idea is an abstraction; so that reason, in transcending experience, can show the necessity of ideas and " ideals," but infer no corresponding reality beyond, whether in nature, or in Man, or in God.
Taken for granted the Kantian hypothesis of a sense of sensations requiring synthesis by understanding, and the Kantian conclusion that Nature as known consists of phenomena united by categories as objects of experience, Green argued, in accordance with Kant's first position, that knowledge, in order to unite the manifold of sensations by relations into related phenomena, requires unifying intelligence, or what Kant called synthetic unity of apperception, which cannot itself be sensation, because it arranges sensations; and he argued, in accordance with Kant's second position, that therefore Nature itself as known requires unifying intelligence to constitute the relations of its phenomena, and to make it a connected world of experience.
After this letter it cannot be doubted that Kant not only differed wholly from Fichte, both about the synthetic unity of apperception and about the thing in itself, but also is to be construed literally throughout.
See Karl Lange, Ueber Apperception (6th ed.
But the possibility of the logical form of all knowledge rests on its relation to this apperception as a faculty or potentiality" (Werke, ed.
But this test of necessity is a wholly secondary one; these laws are not thus guaranteed to us; they are each and all given to us, given to our consciousness, in an act of spontaneous apperception or apprehension, immediately, instantaneously, in a sphere above the reflective consciousness, yet within the reach of knowledge.
The attempt to render the laws of reason or thought impersonal by professing to find them in the sphere of spontaneous apperception, and above reflective necessity, can hardly be regarded as successful.
Such mentally endowed substances might be called souls; but, as he distinguished between perception and apperception or consciousness, and considered that perceptions are often unconscious, he preferred to divide monads into unconscious entelechies of inorganic bodies, sentient souls of animals, and rational souls, or spirits, of men; while he further concluded that all these are derivative monads created by God, the monad of monads.
As to the origin of knowledge, Kant's position is that sense, outer and inner, affected by things in themselves, receives mere sensations or sensible ideas (Vorstellungen) as the matter which sense itself places in the a priori forms of space and time; that thereupon understanding, by means of the synthetic unity of apperception, " I think " - an act of spontaneity beyond sense, in all consciousness one and the same, and combining all my ideas as mine in one universal consciousness - and under a priori categories, or fundamental notions, such as substance and attribute, cause and effect, &c., unites groups of sensations or sensible ideas into objects and events, e.g.
In order to prove this novel conclusion he started afresh from the Cartesian " I think " in the Kantian form of the synthetic unity of apperception acting by a priori categories; but instead of allowing, with all previous metaphysicians, that the Ego passively receives sensations from something different, and not contenting himself with Kant's view that the Ego, by synthetically combining the matter of sensations with a priori forms, partially constructs objects, and therefore Nature as we know it, he boldly asserted that the Ego, in its synthetic unity, entirely constructs things; that its act of spontaneity is not mere synthesis of passive sensations, but construction of sensations into an object within itself; and that therefore understanding makes as well as shapes Nature.
In detail, to express this supposed inner will of thinking, he borrows from Leibnitz and Kant the term " apperception," but in a sense of his own.
Apperception in general thus becomes activity of inner will, constituting the process of attention, passive in the form of impulsive will required for association, and active in the form of decisive will required for understanding and judgment.
When Fichte had rejected the Kantian Soul in itself and developed the Kantian activity of apperception, he considered that soul consists in constructive activity.
Wundt's answer is that inner impulsive will, in the form of passive apperception, forms compound ideas by association; so that all these operations are necessary to the starting-point.
It is the analysis of an aggregate idea (Gesammtvorstellung) into subject and predicate; based on a previous association of ideas, on relating and comparing, and on the apperceptive synthesis of an aggregate idea in consequence; but itself consisting in an apperceptive analysis of that aggregate idea; and requiring will in the form of apperception or attention (Wundt).
It is this unity of apperception which enables us to combine the data of more than one sense, to affirm reality, unreality, identity, difference, unity, plurality and so forth, as also the good, the beautiful and their contraries.
Categories are the forms according to which the combining unity of self-consciousness (synthetic unity of apperception) pluralizes itself through the various functions involved in the constitution of objectivity in different types of the one act of thought, viz.
It is no accident that it was the psychology of apperception and the voluntaryist theory or practice of Herbart, whose logical theory was so closely allied to that of the formal logicians proper, that contributed most spring from a common stock, though to us unknown - namely sense and understanding."
Reference has been made above to the effect upon the rise of the later psychological logic produced by Herbart's psychology of apperception, when disengaged from the background of his metaphysic taken in conjunction with his treatment in his practical philosophy of the judgment of value or what he calls the aesthetic judgment.
In Kantian terminology apperception is (1) transcendental - the perception of an object as involving the consciousness of the pure self as subject, and (2) empirical, - the cognition of the self in its concrete existence.
In (1) apperception is almost equivalent to self-consciousness; the existence of the ego may be more or less prominent, but it is always involved.
Herbart apperception is that process by which an aggregate or "mass" of presentations becomes systematized (apperceptionssystem) by the accretion of new elements, either sense-given or product of the inner workings of the mind.
He thus emphasizes in apperception the connexion with the self as resulting from the sum of antecedent experience.
Apperception is thus a general term for all mental processes in which a presentation is brought into connexion with an already existent and systematized mental conception, and thereby is classified, explained or, in a word, understood; e.g.
The whole intelligent life of man is, consciously or unconsciously, a process of apperception, inasmuch as every act of attention involves the appercipient process.
Immediate spontaneous apperception may seize this supreme reality; but to vindicate it by reflection as an inference on the principle of causality is impossible.
The truth is that Cousin's doctrine of the spontaneous apperception of impersonal truth amounts to little more than a presentment in philosophical language of the ordinary convictions and beliefs of mankind.
The unity of apperception, then, as Kant calls it, is only possible in relation to synthetic unity of experience itself, and the forms of this synthetic unity, the categories, are, therefore, on the one hand, necessary as forms in which self-consciousness is realized, and, on the other hand, restricted in their application and validity to the data of given sense, or the particular element of experience.
Reference of representations to the unity of the object, synthetic unity of apperception, and subsumption of data of sense under the categories, are thus three sides or aspects of the one fundamental fact.
Kant further insisted that this apperception, " I think," is an act of spontaneity, distinct from sense, necessary to regarding all my ideas as mine, and to combining them in a synthetic unity of apperception; which act Fichte afterwards developed into an active construction of all knowledge, requiring will directed to the end of duty.
Further, on his own account, he identifies apperception with the process of attention, and regards it as an act necessary to the general formation of compound ideas, to all association of ideas, to all imagination and understanding.
In accordance with his previous division of outer will into impulsive and decisive, he divides the inner will of apperception into passive apperception and active apperception.
Recognizing, then, three kinds of association in all, he supposes that they are the first processes, by which inner will, in the form of passive apperception, generates ideas from sense.