The universe is composed of a vast multitude of apparently independent things, some animate and others inanimate. While each of these things is a unit in some sense, it is considered also to possess an indefinite number of qualities (or properties). An extremely primitive view of the nature of existence would not recognize the distinction between the physical and the psychical orders. In a more sophisticated view the two orders are distinguished.
Metaphysical criticism of both views gives rise to some problems of great generality and connected with one another.,
- Firstly, the universe, composed of a multiplicity of things, each of which is one, gives rise to the problem of the unity of the thing.
- Secondly, the multiplicity of qualities ascribed to a single thing gives rise to the problem of substance and quality.
- Thirdly, continuous change in the quality of a thing and interaction between different things gives rise to the problem of mutation and causality.
The present section will be devoted to the examination of the above problems, particularly the second one. We shall then proceed to examine the most important aspect of the enigma of universe viz., space and time.
We may deal with the problem of the unity of the thing by asking "why do we consider a particular part of our experience as a single body although it possesses a multiplicity of properties?" The thing possesses an attribute which determines the course of its cognizance as 'whole' at a given moment. The attribute is not the thing itself but is its quality or property. Thus a thing is what has existence as a unit in a particular extension of space and a particular duration of time. But as soon as we ask in what sense a 'thing' is one, it becomes apparent that the unity is not absolute but a matter of degree. Thus, we may, without much difficulty, pronounce a human being as one thing, but when we deal with inanimate aggregates, while we might readily say that a table or a chair is one, we may find it more difficult to decide whether a lump of garden soil is one or many. And even in the cases where our decision is readily given subsequent analysis may prove it wrong.
A thing is not one just because it possesses an unbroken contour, nor does the unity depend upon the identity of its material. On the other hand, common sense regards the many parts of a system which works as a whole as one thing. A thing therefore is one or many according to one's point of view. It is neither absolutely one nor absolutely many. The only thing which could be fully and absolutely one is the whole reality itself, in all other cases the unity would be a matter of degree.
Multiplicity of qualities possessed by what we call one thing is another aspect of the problem. 'IT' i.e., the thing is at once round, red and rough. What is 'IT' which possesses numerous attributes (and how does it possess them)? In traditional language 'it' is the substance to which many qualities belong or in which they inhere.
There is great divergence of ways in which the problem is tried to be solved by different philosophers. One of the simplest solutions is to regard the substance to be just a group of 'primary' qualities which are considered more important or permanent and said to possess the less important 'secondary' qualities. Galileo, Descartes and Locke as well as some modern philosophers have considered such properties as are of prime importance for mechanical physics viz., extension, form, mass etc., as primary qualities. Secondary qualities viz., colour, taste, texture etc. are held by some, including Greek philosopher Democritus, to be subjective and not real. They are mere sensations produced by the action of primary qualities upon sense-organs.
Identification of 'substance' with a group of its important properties may be useful as a working hypothesis in the physical sciences. But as a solution of the metaphysical problem of meaning of substance its value is questionable. In the first place, the distinction between the primary and secondary qualities is quite superfluous because both are ascribed to the 'substance' of a thing. The thing has mass, shape, impenetrability, etc., just as it has colour, taste, roughness, etc. Secondly treatment of secondary qualities as subjective effects on our sense-organs, by philosophers such as Descartes, Galileo Locke, etc., is also not convincing. The argument advanced by these philosophers that they cannot be cognized without the sense-organs is equally applicable to the so-called primary qualities also. In other words the presence of a percipient is essential for the perception of 'primary' qualities of a body as well as 'secondary'. Conversely, extension, shape etc. which arc no* perceived by any one, are exactly the same as a colour which no one sees. Moreover an extension which is totally devoid of the so-called sensible or secondary properties is itself an unreal abstraction because in actual experience, colour, taste etc. are inseparable from extension etc.. Therefore, there must be an ultimate something which possesses both.
Another view regards substance as an unknowable or 'unknown substratum'. According to the scholastic thinkers, the many qualities then 'flow' from the nature of its unknown substratum or substance. According to yet another view, held by Locke etc., the various qualities are consequences of the relations in which each substance stands to other interacting only, i.e., we do not know what things themselves really are, but we know only their attributes or manifestations.
Some philosophers such as Lotze as well as some students of positive sciences regard with disfavor the whole notion of a substantial unity behind the multiplicity of their qualities and attributes. Why not abandon the whole conception of a single substratum and simply say that the thing is the many qualities themselves, they ask. According to this view, then the thing is a collection of attributes and nothing more.
According to the idealist philosophers such as Hume, the unity of the substratum lies not in itself but solely in the percipient's way of thinking. It is a mental fiction.
More recently, Kant also considered the concept of 'substance' simply one form of 'synthetic unity of apperception'. This doctrine of Kant intended by him as a refutation of Hume's associationism is in agreement with the latter on the main point that the bond which united many qualities into one thing is a subjective one and not a reality.
There are others, however, who do not accept the Phenomenalist’s concept of substance as a mere mental fiction. They argue thus: Firstly, the fact that a group of qualities actually functioning as one is no fiction; it is the expression of the nature of the group itself and is as much independent of subjective thought as any single member of the group. Either both are mental fictions or both are the expressions of the real nature of the thing. Secondly, the entire group of quality is never present at any given moment of cognizance. A thing exhibits only a few of its qualities at a time, the vast majority remaining what Locke calls "powers" i.e. ways in which it would behave if certain conditions, absent at the moment, were fulfilled. Most of a thing's indefinite numbers of qualities are, therefore, mere possibilities, some of them remaining 'unrealized' in actual existence.[1] Yet this fact does not destroy the existence of the thing. It actually 'is' and so its existence cannot be identified with its qualities.
We now come to mutation or change. The problem presented by the apparently unceasing mutability of existence is one of the earliest as well as one of the most persistent in the whole range of Philosophy. It is a common feature of the world of experience that within the unity of the one thing there is a successive presentation in time of different states and this fact that the identical and permanent can change gives a paradoxical character to all mutation.
The paradoxical thought that only what is permanent can change has affected the history in different ways. It was the guiding principle of the IONIAN physicists at the very dawn of the Greek philosophy. Later on, Parmenides swung to the extreme view that change, being impossible in a permanent homogenous reality, must be a mere illusion of our senses. Later again, Empidocles sought to reconcile the apparent mutability with the criticism of Parmenides by the theory of re-grouping of elements or atoms in space. At a more developed stage, Plato drew momentous distinction between two orders of being real with its unwearing eternal self-identity and merely apparent where all is change and instability. Plato, however, failed to make it intelligible how these two orders, the eternal and the temporal, are ultimately connected.
Similarly, attempts, to get rid of the paradox by denying its truth, have not been wanting. To escape it by reducing change itself to a baseless illusion appears to be one extreme, while to evade it by refusing to admit any permanent identity of underlying unity in the incessant change is the other. Eleatics and Vedantists are notable among the contributors to the first view while disciples of Heraclitus and Buddhists are those to the other. The former seems to entirely ignore the direct experience and base their concepts purely on a priori logic. The latter, on the other hand, appeal to direct experience in favour of their doctrine that incessant change alone is real. They (the latter) contend that in any real experience we are always presented with the fact of change and transition; we never apprehend an absolutely unchanging content. The positive disproof of the notion is found in its own inherent absurdity
All change must be change of and in something. Where there is no underlying identity, there is nothing to change. Change by itself (apart from a background of identity) is therefore impossible.
The incessant series of successive states which make up the career of a thing are the expression of the thing's structure. To understand the structure of a thing is to possess the key to the succession of its states, to know on what principle each gives way to its successor.
Change, thus apprehended as the embodiment in succession of a principle, is no longer a paradox nor is mutability an unintelligible mystery. Mutability is simply a logical consequence of the existence of any multiplicity forming a systematic whole.