Phil.  And call you this an explication of the manner whereby we are affected with ideas?

HYL.  Why not, Philonous?  Have you anything to object against it?

Phil.  I would first know whether I rightly understand your hypothesis.  You make certain traces in the brain to be the causes or occasions of our ideas.  Pray tell me whether by the brain you mean any sensible thing.

HYL.  What else think you I could mean?

Phil.  Sensible things are all immediately perceivable; and those things which are immediately perceivable are ideas; and these exist only in the mind.  Thus much you have, if I mistake not, long since agreed to.

HYL.  I do not deny it.

Phil.  The brain therefore you speak of, being a sensible thing, exists only in the mind.  Now, I would fain know whether you think it reasonable to suppose that one idea or thing existing in the mind occasions all other ideas.  And, if you think so, pray how do you account for the origin of that primary idea or brain itself?

HYL.  I do not explain the origin of our ideas by that brain which is perceivable to sense—­this being itself only a combination of sensible ideas—­but by another which I imagine.

Phil.  But are not things imagined as truly in the mind as things perceived?

HYL.  I must confess they are.

Phil.  It comes, therefore, to the same thing; and you have been all this while accounting for ideas by certain motions or impressions of the brain; that is, by some alterations in an idea, whether sensible or imaginable it matters not.

HYL.  I begin to suspect my hypothesis.

Phil.  Besides spirits, all that we know or conceive are our own ideas.  When, therefore, you say all ideas are occasioned by impressions in the brain, do you conceive this brain or no?  If you do, then you talk of ideas imprinted in an idea causing that same idea, which is absurd.  If you do not conceive it, you talk unintelligibly, instead of forming a reasonable hypothesis.

HYL.  I now clearly see it was a mere dream.  There is nothing in it.

Phil.  You need not be much concerned at it; for after all, this way of explaining things, as you called it, could never have satisfied any reasonable man.  What connexion is there between a motion in the nerves, and the sensations of sound or colour in the mind?  Or how is it possible these should be the effect of that?

HYL.  But I could never think it had so little in it as now it seems to have.

Phil.  Well then, are you at length satisfied that no sensible things have a real existence; and that you are in truth an arrant sceptic?

HYL.  It is too plain to be denied.