Is opaque to the others which surround it. With regard

to communicability, there is in fact not any difference

of kind, but only of degree. In every case the

communication must be made indirectly, and through the

medium of our outsides. What is true is that, with

certain elements, the ways of expression may be shorter

and less mistakeable; and again the conditions, which

secure a community of perception, are, with certain

elements, more constant and more subject to our control.

So much seems clear, but it is not true that our

physical experiences have unity, in any sense which is

Inapplicable to the worlds we call internal. Nor again,

even in practice, is it always more easy to communicate

an outer than an inner experience. In brief, regarded as

an existence which appears in a soul, the whole world

for each is peculiar and private to that soul. But, if

on the other hand, you are considering identity of

content, and, on that basis, are transcending such

particular existences, then there is, at once in

principle, no difference between the inner and the

outer. No experience can lie open

to inspection from outside; no direct guarantee of

identity is possible. Both our knowledge of sameness,

and our way of communication, are indirect and

inferential. They must make the circuit, and must use

the symbol, of bodily change. If a common ruler of souls

could give to any one a message from the inside, such a

message could never be handed on but by alterations of

bodies. That real identity of ideal content, by which

all souls live and move, cannot work in common save by

the path of external appearance.

And, with this, we are led to the question of the

identity between souls. We have just seen that immediate

experiences are separate, and there is probably no one

who would desire to advocate a contrary opinion. But

there are those, I presume, who will deny the

possibility of two souls being, in any respect, really

the same. And we must endeavour very briefly to clear

our ideas on this matter.

It would be, of course, absurd to argue that two

persons are not two but only one, or that, in general,

differences are not different, but simply the same; and

any such contention would be, doubtless, a wilful

paradox. But the principle of what we may call the

Identity of Indiscernibles, has quite another meaning.

It implies that sameness can exist together with

difference, or that what is the same is still the same,

however much in other ways it differs. I shall soon

attempt to define this principle more clearly, but what

I would insist on, first, is that to deny it is to

affront common sense. It is, in fact, to use words which

could have no meaning. For every process of psychical

Association is based on this ground; and, to come to

what is plainer, every movement of our intellect rests

wholly upon it. If you will not assume that identity

holds throughout different contexts, you cannot advance

one single step in apprehending the world. There will be

neither change nor endurance, and still less, motion

through space of an identical body; there will

neither be selves nor things, nor, in brief, any

intelligible fact, unless on the assumption that

sameness in differents is real. Apart from this main

principle of construction, we should be confined to the

feeling of a single moment.

And to appeal to Similarity or Resemblance would be a

futile attempt to escape in the darkness. For Similarity

itself, when we view it in the daylight, is nothing in

the world but more or less unspecified sameness. I will

not dwell here on a point which elsewhere I have

possibly pursued ad nauseam. No one, perhaps, would ever

have betaken himself to mere resemblance, unless he had

sought in it a refuge from the dangers of Identity. And

these dangers are the product of misunderstanding.

There is a notion that sameness implies the denial of

difference, while difference is, of course, a palpable

fact. But really sameness, while in one respect

exclusive of difference, in another respect most

essentially implies it. And these two "respects" are