Sense-Data

‘Sense-data’ are the things that are immediately known in sensation. Examples are colours, sounds, smells, hardnesses, roughnesses, and so on.

‘Sensation’ is the experience of being immediately aware of these things.

Thus, whenever we see a colour, we have a sensation of the colour. But the colour itself is a sense-datum, not a sensation.

The colour is that of which we are immediately aware, and the awareness itself is the sensation.

If we are to know anything about the table, it must be by means of the sense-data—brown colour, oblong shape, smoothness, etc. These we associate with the table.

But we cannot say that the table is the sense-data, or even that the sense-data are directly properties of the table.

Thus, a problem arises as to the relation of the sense-data to the real table, supposing there is such a thing.

The real table, if it exists, we will call a ‘physical object’.

Thus we have to consider the relation of sense-data to physical objects. The collection of all physical objects is called ‘matter’. Thus our 2 questions may be re-stated as:

1. Is there any such thing as matter?
2. If so, what is its nature?

Bishop Berkeley (1685-1753) first proposed why the immediate objects of our senses as not existing independently of us.

His Three Dialogues between Hylas and Philonous, in Opposition to Sceptics and Atheists, prove that:

• there is no such thing as matter at all, and
• the world consists of nothing but minds and their ideas.

Hylas has believed in matter. But he is no match for Philonous, who mercilessly drives him into contradictions and paradoxes, and makes his own denial of matter seem, in the end, as if it were almost common sense.

The arguments employed are of very different value. Some are important and sound, others are confused or quibbling.

But Berkeley has shown that:

• the existence of matter can be denied without absurdity, and
• if there are any things that exist independently of us they cannot be the immediate objects of our sensations.

We commonly mean by ‘matter’ something which is opposed to ‘mind’. It is something which we think of as occupying space and as radically incapable of any sort of thought or consciousness.

It is chiefly in this sense that Berkeley denies matter. He believes that the sense-data from the existence of the table are really signs of the existence of something independent of us. But he denies that this something is non-mental, that it is neither mind nor ideas entertained by some mind.

He admits that there must be something which continues to exist when we go out of the room or shut our eyes, and that what we call seeing the table does really give us reason for believing in something which persists even when we are not seeing it.

But he thinks that this something cannot be radically different in nature from what we see, and cannot be independent of seeing altogether, though it must be independent of our seeing.

He is thus led to regard the ‘real’ table as an idea in the mind of God. Such an idea has the required permanence and independence of ourselves, without being—as matter would otherwise be—something quite unknowable, in the sense that we can only infer it, and can never be directly and immediately aware of it.

Other philosophers since Berkeley have also held that, although the table does not depend for its existence upon being seen by me, it does depend upon being seen (or otherwise apprehended in sensation) by some mind—not necessarily the mind of God, but more often the whole collective mind of the universe.

This they hold, as Berkeley does, chiefly because they think there can be nothing real—or at any rate nothing known to be real except minds and their thoughts and feelings. We might state the argument by which they support their view in some such way as this: ‘Whatever can be thought of is an idea in the mind of the person thinking of it; therefore nothing can be thought of except ideas in minds; therefore anything else is inconceivable, and what is inconceivable cannot exist.’

I think that such an argument is fallacious. Those who advance it do not put it so shortly or so crudely.

A majority of philosophers have held that there is nothing real except minds and their ideas.

Such philosophers are called ‘idealists’.

They explain matter as either:

• that matter is really nothing but a collection of ideas, like Berkeley, or
• that what appears as matter is really a collection of more or less rudimentary minds, like Leibniz (1646-1716).

These philosophers deny matter as opposed to mind. But in another sense, they admit matter.

Both Berkeley and Leibniz admit that there is a real table.

• But Berkeley says it is certain ideas in the mind of God.
• Leibniz says it is a colony of souls.

Thus both of them only diverge from the views of ordinary mortals in their answer to what objects are.

We have discovered that:

• If we take any common object that is known by the senses, what the senses immediately tell us is not the truth about the object as it is apart from us.
• Our senses only tells about the truth about certain sense-data which depend on the relations between us and the object.

Thus what we directly see and feel is merely ‘appearance’, which we believe to be a sign of some ‘reality’ behind.

But if the reality is not what appears, have we any means of knowing whether there is any reality at all? And if so, have we any means of finding out what it is like?

• Leibniz tells us it is a community of souls.
• Berkeley tells us it is an idea in the mind of God.
• Sober science tells us it is a vast collection of electric charges in violent motion.

Among these surprising possibilities, doubt suggests that perhaps there is no table at all.