Monism

The ending ‘-ism’ suggests a particular theory or school; but in the case of ‘monism’ this is somewhat misleading. Less misleading is to think of certain philosophies as monistic in respect of some central doctrine, realizing that which doctrine this is may differ widely from case to case. This approach gives the flexibility to see that a philosophy which is from one perspective a variety of monism may well be, in respect of some other central doctrine, not monistic at all. For instance, Spinoza took the view that there was and could be only one substance (see Substance). But he also held that this substance had infinitely many attributes, of which all but two (the mental and the physical) are unknown to us. There is nothing wrong with calling Spinoza a monist – provided it is said with an eye to a particular feature of his system.

With that warning in mind, we can say that the most common use of ‘monism’ is to describe philosophies which maintain that there is, ultimately, only one thing, and that ‘the Many’ are aspects of it or, to a more radical way of thinking, simply an illusion resulting from our mis-perception of the One. What they are not, for an ontological monist, is a collection of independent existences. Bertrand Russell once wrote that Hegel thought reality was like a tin of treacle, whereas he (Russell) thought it was like a heap of shot – the metaphor is even better if we keep the treacle in mind and forget the tin.

A spectacular early example of monism is found in the thought of Parmenides, who obscurely argued that reality could consist only of one thing, changeless and undifferentiated, and that the appearance of plurality was illusory (see Parmenides §7). In later antiquity, Plotinus influentially declared that everything emanated from another such changeless and undifferentiated entity, ‘the One’. In the nineteenth century the view (associated in particular with F.H. Bradley) became widespread that relations between distinct entities cannot ultimately be real: for if two such entities are related by some relation R, there would be need of further relations to relate the relation R to each of them, and so on into infinite regress. Therefore there can only really be one thing, for if there were more they would have to be in some way related to each other. A similar argument occurs in Indian thought (see Monism, Indian §3). Those who are sceptical will suspect that it rests on the tacit and dubious assumption that a real relation would have to be a kind of thing, like the things it relates.

A very different group of doctrines is also often called ‘monism’: those doctrines which assert, not that there is only one thing, but that there is ultimately only one kind of thing, one basic stuff of which the many kinds we observe are variant forms. Tradition unreliably has it that Thales, the earliest Greek philosopher of whom we have record, taught that this basic substance was water; a little later Anaximenes held a similar view, but chose air as his elemental stuff. They were therefore monists in this second sense, as is anyone who believes that the variety of the world is really nothing more than different arrangements of atoms which are themselves identical (see Atomism, ancient).

One version of the ‘one stuff or more?’ debate has been especially prominent in modern philosophy: are there two kinds of substance – matter and mind – or only one, and, if so, which? Here the question is not ‘are there one or more?’ but ‘are there one or two?’, and when philosophers speak of monism as the alternative to dualism (without saying one or two what?) it is nearly always this issue that they are referring to. (A quite different use of the term ‘dualism’ is used in religious thought to refer to the view that the world is the work of two powers, one good and one bad – see Manicheism §§1, 4.) In modern times, Descartes is the classic exponent of mind–body dualism, though hardly its inventor – he was only giving precision and proof to the very old idea that as well as matter there are spirits or souls, and that the latter are very different in kind from the former. Ranged on the other side are various styles of monist. There is idealist monism, typified by Berkeley, which holds that there are only minds or spirits, and that material bodies are nothing but a way of speaking about mental states (see Phenomenalism); there is material monism, steadily more popular with the rise of the natural sciences, which views everything as material, and reduces the supposedly mental to facts about matter (see Materialism in the philosophy of mind). And there is a doctrine associated in particular with the names of Mach, James and Russell, which sees the mental and the physical as different aspects of a single basic stuff that in itself is neither mental or physical (see Neutral monism).

Because of its very general meaning, ‘monism’ lends itself to a wide variety of uses easily understood from their context. Thus one may see ‘value-monism’ – meaning an ethical system which recognizes only one thing as having value in itself, for example happiness (see Utilitarianism). And one may speak of monism about truth, meaning that there is one unique set of truths – in opposition to pluralism, relativism and perspectivalism, according to which conflicting or incommensurable views may be equally true.