Any investigation into the nature of the self is closely bound up with the mind-body problem and questions of personal identity. However, there is a long philosophical tradition of treating the self as a concept worthy of consideration in its own right.
The self is not an easy thing to define, but Galen Strawson suggests the following:
I propose that it is (at least) the sense that people have of themselves as being, specifically, a mental presence; a mental someone; a single mental thing that is a conscious subject of experience, that has a certain character or personality, and that is in some sense distinct from all its particular experiences, thoughts, and so on, and indeed from all other things.
Philosophers have understood the concept in each of these capacities, and in the following it will most commonly be understood as the conscious subject of experience.
The term ‘self’ often appears in compound terms like ‘self-consciousness’ or ‘self-knowledge’: in such constructions it is understood as both the subject and object of awareness or knowledge. At first glance, therefore, the self seems to be a thing or a substance, like other objects of knowledge. This was how René Descartes described the self. According to his theory of substance dualism, the self is a mental substance, the nature of which is to think.
I knew I was a substance whose whole essence or nature is solely to think, and which does not require any place, or depend on any material thing, in order to exist. Accordingly this ‘I’ – that is, the soul by which I am what I am – is entirely distinct from the body. Discourse on Method IV
The notion of ‘substance’ needs clarification. Aristotle, whose definition of the concept of substance served the Middle Ages and beyond, distinguished between substance and properties. Substance is the underlying ‘stuff’ to which properties are attached. So we can describe a table as being new, unvarnished, six-legged and of a certain height: each of those adjectives describes properties belonging to the table. Aristotle noted that such properties can change: over time, the table will age, may acquire a coat of varnish or lose a leg, and perhaps be lowered – but the table in some sense remains as a substance. Aristotle also made the case that properties cannot exist unless they are attached to a substance: a table may be unvarnished, but the property ‘unvarnished’ cannot exist on its own (something must be unvarnished for the property to exist). This account crucially explains how change occurs: an object remains the same over time because its properties alter but its substance remains.
And so for Descartes, the self is the underlying mental substance which remains even though its properties (ie thoughts, desires, perceptions) may change. Of course, the theory of substance dualism is problematic for several reasons (see Mind and Body). But the strongest argument against Descartes’ conception of the self came from David Hume.
Empiricist philosophers tend to find substance a problematic concept because we never perceive a thing separately from its properties. For a rationalist like Descartes, it may seem possible to mentally subtract colour, shape, texture etc from a thing and conceive of a hidden, underlying substance. But empiricists are sceptical of things that cannot be perceived, and claim that it is impossible to comprehend the notion of an object without its properties. For David Hume, this scepticism extended even to the notion of a self.
For my part, when I enter most intimately into what I call myself, I always stumble on some particular perception or other, of heat or cold, light or shade, love or hatred, pain or pleasure. I never can catch myself at any time without a perception, and never can observe any thing but the perception... I may venture to affirm of the rest of mankind, that they are nothing but a bundle or collection of different perceptions, which succeed each other with an inconceivable rapidity, and are in a perpetual flux and movement. Treatise 1.4.6
This is known as the ‘bundle theory’ of the self. Hume rejects the notion of a substance that underlies our experiences, and instead claims that we simply are our sensations, feelings, ideas etc. The notion of a unified self arises simply from our habit of thinking of collections as unities. Some modern philosophers similarly believe that the self is merely a convenient fiction, a point-of-view rather than a thing, or in Daniel Dennett’s phrase a ‘centre of narrative gravity’. Effective as Hume’s argument is, it raises interesting metaphysical questions about how properties combine, and the theory has serious implications for the question of personal identity persisting over time.
Hume’s scepticism about the self led to something of a crisis in European philosophy – a crisis that inspired Immanuel Kant to provide a new and sophisticated account of the self.
Kant makes a crucial distinction between reality as it is in itself, and as it appears to us. We have no grasp at all of the nature of ‘things in themselves’: reality before we experience it simply cannot be imagined. To conceive of something, or to grasp or comprehend it, is to turn it into an experience – and that, says Kant, is a process performed by the self or subject. In this view, therefore, the self has a crucial role as the structuring element in our experiences, the organising point of view necessary for any experience at all.
Obviously we can experience the external world and this occurs mainly, as the empiricists claimed, through perception. But the raw material of perception needs to be shaped, structured and interpreted by ‘concepts of the understanding’ before it counts as an experience. In a famous phrase, Kant described how the act of experience is as much the responsibility of the subject as of the object itself:
Thoughts without content are empty, intuitions without concepts are blind. Critique of Pure Reason 86
So the mind processes the raw perceptions that reach it, and turns them into the sorts of things that we can comprehend. This involves imposing principles of thought like space and time, causality and – yes – substance. It makes no sense to talk of a world in itself, before it has been structured spatially, temporally, causally and so on. Such a world is beyond our understanding. But the self exists to actively construct, from these raw materials, a three-dimensional world of persistent objects through which we move.
Kant’s account has several advantages. Firstly, it explains our inclination to see the world – and the self – in terms of substance: precisely because we interpret the world as substantial. Secondly, it explains the self not as a thing but in terms of its function, giving the self a crucial role in the construction of our experience. This type of ‘functionalist’ account is very much a modern theory of mind, but its roots lie in Kant’s attempt to restore the self to a central role in our experience. And thirdly, Kant makes the self important again. Not only does the mind actively construct our experience of the world, but without such a capacity, without a point-of-view, it would not be possible to experience anything at all.
Descartes’ investigation relied on the certainty of first-person knowledge. Even though he was able to doubt the reality of everything outside himself, his own thoughts were indubitable: he could doubt that he was a body, in a particular place at a particular time, and so on – but he could not doubt that he was doubting. For Descartes, this first-person knowledge was a foundation upon which he could build other knowledge (cogito ergo sum etc). But the method of systematic doubt opened up the possibility of scepticism. Although I may be certain of my own thoughts, I cannot be certain of anything else. Descartes himself resorted to the benevolence of God to resolve that problem, but philosophers are generally unwilling to follow him in this respect. The logical conclusion of this sceptical approach is solipsism, the position that one’s thoughts are in fact the only things that exist.
Absurd as this position sounds, it is grounded in some genuine philosophical puzzles. It seems legitimate to question the subjective experiences of other people, as I cannot know other minds in the same way I know my own (this is generally described as the problem of other minds). I am aware of my own mental states directly: if I am in pain, then I know it and I cannot be mistaken. But this knowledge is private: no other person could ever experience my pain. Accordingly, I can never experience another person’s pain, and therefore I have to infer its existence from their behaviour: wincing, moaning and so on. In fact, I can never be sure that other people even have minds: they could be zombies or automata, replicating behaviour without feeling or experiencing anything internal. To infer that others have minds like my own is to make a hasty generalisation based on only one case – my direct experience of my own mind. This argument from analogy seems to fit with our common-sense view of the world, but has very little philosophical substance. In fact, it may not be possible at all to argue against the solipsist or even to prove the existence of other minds.
In the twentieth century a different conception of the self arose in response to this problem. Rather than describing the self as private and inaccessible, philosophers began to explore the ways in which the self arises in a more public way, a way that depends as much upon other people as upon ourselves. This notion of intersubjectivity recognises that we are entangled in complicated ways with the world and with other people, other subjectivities: that our social acts take place in broad fields of shared experience. We are, in a sense that is perhaps not surprising, constituted by the world around us, and by the way we are perceived by other people. This is true in a number of areas, not least gender: as Simone de Beauvoir famously noted,
One is not born, but rather becomes, a woman... it is civilisation as a whole that produces this creature. The Second Sex 267
The intersubjective fields of our experience are numerous, complex and shifting: they include shared notions like gender, race, history, genre, family and so on. Perhaps the most obvious example, however, is language.
The later Wittgenstein was particularly interested in how we could have the type of radically subjective and private experience described by Descartes. His conclusion was that we could not, because of the intimate connection between our experience and our language. He was puzzled by what it could mean to describe something as, eg my pain.
If I say of myself that it is only from my own case that I know what the word ‘pain’ means—must I not say the same of other people too? And how can I generalise the one case so irresponsibly? Philosophical Investigations §293
This, of course, is a rejection of the argument from analogy. Instead, Wittgenstein argues that the way we speak misleads us. Imagine I am a commuter who catches the 7.22 to London every morning. I might well refer to the 7.22 as ‘my train’ – as in ‘my train was late today’. But what is it about the train which I am using to identify it as ‘mine’? This is not the usual sense of the word, the way I might use it to refer to ‘my briefcase’. What identifies it as ‘my’ train is merely the fact that I catch it every morning. Other commuters regularly catching the 7.22 could also be referring to it as ‘their’ train. Thus, ‘my train’ is nothing like ‘my briefcase’ (which other commuters cannot call theirs). What I am referring to in ‘my train’ is, in fact, a shared and publicly meaningful concept which, only superficially, looks as if it belongs to me alone (like ‘my briefcase’). Wittgenstein’s argument is that ‘my pain’ is the same as ‘my train’ – there is nothing about it to identify it with me personally, but a lot that identifies it as a public entity (we all know about pains – we might even talk about having the same pain).
Now someone tells me that he knows what pain is only from his own case!—Suppose everyone has a box with something in it: we call it a ‘beetle’. No one can look in anyone else’s box, and everyone says he knows what a beetle is only by looking at his beetle.—Here it would be quite possible for everyone to have something different in his box. One might even imagine such a thing constantly changing.—But suppose the word ‘beetle’ had a use in these people’s language?—If so it would not be used as the name of a thing. The thing in the box has no place in the language-game at all; not even as a something: for the box might even be empty.—No, one can ‘divide through’ by the thing in the box: it cancels out, whatever it is. Philosophical Investigations §293
We operate, therefore, in a public world of shared meanings, in fields of intersubjective experience. It is this public world that makes my experience intelligible, and the very fact that this shared world exists seems to demand the existence of other minds. The self is situated in a world of meaning that is to a large extent shared by others. It is hard to resist such a description, although it is important to realise what a radical departure it represents from our starting point: the isolated, private and subjective Cartesian ego.