The role of sensus communis in Aristotle, Thomas Aquinas, Locke and Kant
Suzuki, Albert Ichiro
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The purpose ot this thesis is to present a concentrated study of the "Sensus Communis" in the Philosophy of Aristotle, Thomas Aquinas, Locke, Leibniz and Kant. The conception of the "Sensus Communis" was first introduced in the field of psychological study by Aristotle. In the De Anima, after he examined the function of each peripheral sense-organ of sight, hearing, smiling, tasting and touch, he proceeded to the analysis of the "Sensus Communis," which discriminates between these particular perceptions which are perceived by the five senses and unites them into perceptual wholes. When we reflect on the matter, every object that falls under the senses will be apprehended as existing or operating somewhere and sometime. A rose, for example, is not merely red and fragrant, it also has surface, extension, shape, solidity, a definite size, and even a local motion if it sway in the breeze. A song, for instance, is not merely a series of auditory stimuli. It also has a definite tempo, a meter, accents and rhythm. None of the spatial features of the rose and none of the temporal characteristics of the melody are perceived by any one of the five senses alone. Thus Aristotle started to enumerate those common qualities which he named "Common Sensibles," i.e., motion, form, number, magnitude and rest (and time). As we can easily see from this listing of the "Common Sensibles" these qualities imply spatio-temporal relation which is inherent in all sense-perception. Aristotle himself seems to have noticed this end attributed all the common properties to the quality of motion, from which he also attempted to explain the conception of time. But while he was groping his way in the field of sense-experiences, he encountered several problems which seemed to have a great significance in interpreting the activity of sense-perception. First of all, he noticed that, though each sense-organ perceives different qualities of the object, we are not sensing the object as a manifold. Smell of the rose and color of the same are two different experiences. But we are sensing the same rose and never doubt whether it is two or one. Ther must be, accordingly, some principle of the unification of sense-perception which is not furnished in each proper peripheral sense-organ. Aristotle named this synthetic activity of the mind central sense. The closer examination of the matter will disclose several important facts that the existence of such a synthetic faculty is inevitable and necessary. For instance, self-consciousness or the perception that we perceive must be one of the synthetic faculty. Or lower level judgment, in so far as applies to the comparison, contrast, and discrimination of the deliverances of sense-organs, may be said to belong to this central power of sense-perception. Beside these, imagination which is residual sense-images of the reproduction of once-acquired sense-images, i.e., memory and reminiscence, must have their principle which operate for their preservation and reproduction, no matter whether it is voluntary power or involuntary. Thus, the role of Sensus Communis or central sense of Aristotle can be summarized: (1) the unification of the primary sensibles or the complete act of sense-perception; (2) the perception of perception, i e., consciousness; (3) the suspension of consciousness or sleep; (4) the cognition of the "common sensibles"; (5) judgment, in so far as it applies to the comparison, contrast, and discrimination of the deliverances of senses; (6) imagination, or the residual sense images; (7) memory (including reminiscence), or the voluntary and involuntary reproduction of sensation. In the Thomistic formula, sensus communis is classified under the subdivision of Sensus Interiores and is defined as communis radix omnium sentium. However it is not clear whether by this communis radix Thomas meant merely a higher faculty of the mind or some a priori principle of acquiring the external world. From this we can only understand a common ground in which all exterior sense functions are rooted. This analysis of Sensus Communis inevitably leads us to somewhat noetic activity of our mind. If we interpret sense-organs as several gates through which the outside world will be brought into us, Thomas' distinction of the inner and outer senses is to be said appropriate. But in that case, how we can segregate purely noetic activity of the intellect from the inner sense? For Thomas, the dividing principle was whether the faculty was of animal or of man. The problem is a little more complicated in Locke, who refuted all the possibility of innate principles. Therefore, he could not explain how we can acquire the faculties of sensation and reflection, which he assigned respectively to external and internal observation. The point was sharply criticized by Leibniz. According to him, perception is divided into two: the lower perception of unconsciousness, in which there is union of a manifold in what is perceived, but of neither is the subject clearly aware, and the higher perception which is called by him "apperception" in which the perceptions have reached a certain measure of clearness and distinctness and in which the subject is aware of the multiplicity which is united in the content apprehended. And he attributed this synthetic power to this notion of awareness and renamed it apperception. Under the conception of apperception, Leibniz includes the concept that I have; the concept of the self; the concept of my thought, which derives from our inner experience. Further analysis of the matter leads us to the notion of succession of perception which affects our inner sense and awakens in us the idea of duration. However, for Leibniz, the duration itself is not made of the collection of the particular perceptions. Just as space can not be determined if there is no fixed or immovable body, so time can not be determined without something uniform in nature. Thus he posits an uniform intelligible motion which is the measure of non-uniform, particular motions. He infers the conception of uniform motion from the infinite duration in God. This Leibnizian interpretation of the uniform intelligible (not sensible) time was adopted by Kant as an a priori form of the inner sense. It is a pure form of the sensible intuition through which the outer world of things-in-themselves are given to us as phenomena or representation. Kantian conception of time as a form of intuition does not derive from our experience. Kant distinguishes empirical time (which can be divisible as the object of perception) from time a priori. The former can be apprehended by the inductive study of 'motion' which we can see in Aristotle's empiricism. However, we cannot neglect the fact that, when Aristotle discussed the problems of motion and time as one of the "Common Sensibles" and sought for the inner principles which perceive such qualities, the way to the transcendental philosophy has already been prepared, though it was not explicitly stated in Aristotle and therefore left as problematical.
Thesis (M.A.)--Boston University