258 THE GROUNDWORK OF SCIENCE

forth, we shall find that it stands in close relation to our

perception and idea of "change."

When some change occurs, or when anything strikes us as

being a new thing, we spontaneously look out to see what

has brought it about what is its cause. And very often our

investigation is quite satisfactorily repaid. We find what the

cause was, and that we can by experiment again produce the

effect whenever we will.

Think over the matter as we may, when we perceive a

change, or that a new existence has come into being, we are

at once certain that some cause must have produced it. If we

have gone out of doors, leaving our library window open, and

on our return find it shut, we are at once absolutely certain

that some person or thing must have shut it. If an infant

begins to cry violently without any external cause, we are

sure that it has experienced some painful feeling, produced

through some internal modification. If we find in a bird-cage

which has long been shut up and tenantless, a living thrush,

the notes of which have attracted our attention, we are at once

as certain as it is possible to be that, if it did not find its

way in itself, someone must have placed there this, for us,

new existence.

This mental conviction of ours is no negative one, such, e.g.,

as that " We cannot conceive such changes or new existences

without a cause," but that we positively do see "that every

change or new existence is, and must be, due to some cause?

This proposition, indeed, expresses an intellectual intuition

which is for us a necessary and universal truth, and one self-

evident. As such, of course, it is quite incapable of proof;

but a little pondering over it will, we think, make its self-

evidence quite clear, and show that it is no blind habit of

mind " due to custom," as Hume said (as if the origin of any

idea could be explained by such a notion !) but is one seen to

be necessarily true,

forth, we shall find that it stands in close relation to our

perception and idea of "change."

When some change occurs, or when anything strikes us as

being a new thing, we spontaneously look out to see what

has brought it about what is its cause. And very often our

investigation is quite satisfactorily repaid. We find what the

cause was, and that we can by experiment again produce the

effect whenever we will.

Think over the matter as we may, when we perceive a

change, or that a new existence has come into being, we are

at once certain that some cause must have produced it. If we

have gone out of doors, leaving our library window open, and

on our return find it shut, we are at once absolutely certain

that some person or thing must have shut it. If an infant

begins to cry violently without any external cause, we are

sure that it has experienced some painful feeling, produced

through some internal modification. If we find in a bird-cage

which has long been shut up and tenantless, a living thrush,

the notes of which have attracted our attention, we are at once

as certain as it is possible to be that, if it did not find its

way in itself, someone must have placed there this, for us,

new existence.

This mental conviction of ours is no negative one, such, e.g.,

as that " We cannot conceive such changes or new existences

without a cause," but that we positively do see "that every

change or new existence is, and must be, due to some cause?

This proposition, indeed, expresses an intellectual intuition

which is for us a necessary and universal truth, and one self-

evident. As such, of course, it is quite incapable of proof;

but a little pondering over it will, we think, make its self-

evidence quite clear, and show that it is no blind habit of

mind " due to custom," as Hume said (as if the origin of any

idea could be explained by such a notion !) but is one seen to

be necessarily true,