resulting propositions which is relevant to the external world. The deductions to be drawn from these generalizations of relativity deal with particular terms, and the whole meaning for physics of propositions such as (6) or (3) is that when a term which is a C occurs, we can say that it is a D also; or to take the specific example of (3), that when a body is moving with velocity v, we may substitute for its mass in terms of this velocity according to (3), and so deduce other particular facts about, for example, its path in space. The theory of relativity takes as its data the particular facts of the external world and arranging and collating them in general propositions -by means of probability inference-interprets its results in terms of the deductions which can be made from certain facts which are known, to other particular facts which may or may not be known. Correlation between different facts is the only aim of science, and it would certainly be true to say that it is correspondences between data which alone are required (p. 125). The reality of these facts which form the material of physics is not questioned. They are the reality with which science is concerned and indeed the only reality. And the assertion that these facts are the only reality, leads at once to the view of the concept taken by science. Concepts are employed merely as abstracts to facilitate the arrangement and collation of the particular facts which are themselves the only reality.

The advances made by the theory of relativity may be considered in the light of these remarks. The concept of mass, for example, has been fundamentally modified. Logically speaking, it was found that the facts in question could be grouped more satisfactorily in universal propositions of a different form and the concept-the class name for terms having certain properties

was amended. A second example may be taken. The concept of length, introduced at a very early stage in physics has been severely modified. In Weyl's developments and in the work of Eddington, the concept of length is used in such a way that the unit of length is a function of the three space co-ordi

nates and of the time co-ordinate. In fact the unit of length is not constructed for all times and all places but on the contrary, each point of space time has its own gauge system.

In the work of Eddington which has put forward the latest developments from a strictly methodological point of view, an assumption is put forward called the "Comparability of Proximate Relations." This postulate is introduced to bridge the gap between the gauge systems of discrete points and asserts the comparability of neighbouring gauge systems. It is introduced at present tentatively, as the simplest way of building up a common system from the gauge systems of the points of space time, which physics seems to require. From the standpoint of physics the introduction of this assumption or of a similar one is entirely justified.

Conclusions.

It must be mentioned explicitly that the correlation of characters is the most important business of science, for the proposition of relativity and other branches of science can all be reduced to propositions of this kind. If "causality" is involved in science, it must accordingly be present in propositions of these types; otherwise it is irrelevant. In making assertions as to the nature of "cause" employed in relativity theory, one should, I think, reduce the propositions under discussion to their fundamental forms. It will then be a comparatively simple matter to decide the question. But I would like to stress the fact that whatever is said about the subject must be reduced to questions of the correlation of characters, and that indeed there is no further question of whether relativity uses the notion of "substance or cause underlying experience " (p. 123).

The constructed concepts of relativity enable us to group together masses of facts and the investigation of the relative merits of alternative concepts for this purpose-this constitutes a large part of the work of Weyl and Eddington—is an important part of scientific theorizing.

To its view that the concept is an abstraction, science will allow no exception. The mind is not in a privileged position, but like other concepts is constructed to facilitate the description of the world and the correlation of facts. It is part of the business of psychology to discover all the factors which are involved in the propositions in which the concept occurs. But, formally and methodologically, we have here a study not essentially different from the investigation of the factors involved in the notion of mass in physics. But it cannot be allowed that the mind is concrete experience (p. 124) in any sense in which the assertion would be inconsistent with the abstract character of the concept. In psychology, as in other branches of physics, the sensations are the data from which we start, and progress consists in linking together different facts of sensation.

The theory of relativity has made great advances because it has put forward important modifications of the concepts currently employed in science. It has in particular suggested that the older idea of length which attempted to build up quantitative physics on the basis of one unique unit of length is not the most useful concept to employ. It substitutes a concept of length which, though it depends on the precise neighbourhood of space time in which it is applied, does not imply any change in the status of the mind as used in science. New variables are involved in propositions about length, beyond those previously thought to be relevant. The recognition that the temperature was a factor to be considered in propositions about length was an advance, methodologically of the same type. It would therefore, I think, be unjustifiable to conclude that the new concepts of relativity allow any deductions whatever to be made as to the nature of mind. The theory of relativity and physics as a whole takes up its stand on the reality of sensations and gradually constructs the concepts which are most suitable expressions of the correlations between the various facts of experience.

Meeting of the Aristotelian Society at 21, Gower Street, W.C.1,

on March 6th, 1922, at 8 P.M.

*

VIII. THE LOGIC OF THE VEDANTA.

By S. N. DASGUPTA.

THE word Vedanta means literally the concluding parts of the Vedas also called the Upanisads, of which the earliest ones were composed probably about 500 B.C. An extremely condensed exposition of the purport of these earlier Upanisads was attempted by Bādarāyana probably about 200 B.C., and this work is called the Vedanta sutras. It was commented on and interpreted in totally different ways by many philosophers of later times. The earliest and best-reputed commentary now available is that which was attempted by Sankara in the eighth century A.D. The view expressed by Sankara as the correct interpretation of the Vedanta sūtras and the Upanisads was further elaborated and supplemented in dialectical arguments by succeeding generations of his followers down to the seventeenth century A.D. It is the view of the Vedanta propounded by Sankara and his followers which will form the subject matter of this paper. I shall try to show the course of the development of the logical position of the Vedanta in its different stages of growth in relation to, and in contrast with, the Buddhist philosophy and the realism of Nyāya-Vaiśeṣika philosophy, with which it was always contending.

Though individual exponents from sectarian interests have always held that the Upanisads preach a consistent and fully developed system of philosophy, it is by no means certain that

* The Vedic literature comprises of the four Vedas (collections of hymns), the Brāhmaṇas, ritualistic commentaries on the hymns, containing many kinds of other speculations, and the Upanisads (secret doctrines) which are separate treatises forming the concluding portions of these Brāhmaṇas.

N

such a contention can be justified. But a study of the Upanisads makes it clear that certain lines of thought are very much more emphasized than others. Sankara laid emphasis on these, and sought to explain away all other texts that came in conflict with them. We, therefore, start from these as the nucleus of the Vedanta thought. The mean feature of this thought is a sort of inspired belief or conviction of the Upanisad sages that the highest ultimate and absolute truth, the Brahman (lit. great) is the inmost self in us. This truth is not arrived at by a process of logical reasoning, but it is realized as the inspiration of the moment. But what is this self that the Upanisads describe as the highest and supreme reality? In a certain passage five kinds of self are distinguished, self as gross material body, self as vitality, self as will, self as conscious states, and self as bliss, and it is held that this last is the true self, true reality. The Upanisads do not seem to think that any definition of this ultimate truth is possible, for it is beyond everything else and all else falls far short of it. It can therefore only be pointed out as not this, not this, but its positive nature cannot be explained in terms of anything else. The story is told that a certain person went to a teacher of Vedānta and wished to be instructed about the nature of this highest truth, but the teacher did not say anything, and when the pupil repeated his question for a number of times, the teacher replied that he (the pupil) could not understand him though he (the teacher) was instructing him from the very beginning by his silence, for truth was silence. It may no doubt seem very mystical that no positive definition of the highest reality could be given and that it should be regarded as inexpressible. But the Upanisad hypothesis was such that there was no way of defining the highest reality by the enumeration of any of its characteristics. The highest reality was not a matter of mere abstraction for it was felt as immediate and concrete, and was believed to be directly given in experience. The difficulty of giving a definition was of a methodological character, for as it