HYL.  I acknowledge you have proved that Matter is impossible; nor do I see what more can be said in defence of it.  But, at the same time that I give up this, I suspect all my other notions.  For surely none could be more seemingly evident than this once was:  and yet it now seems as false and absurd as ever it did true before.  But I think we have discussed the point sufficiently for the present.  The remaining part of the day I would willingly spend in running over in my thoughts the several heads of this morning’s conversation, and tomorrow shall be glad to meet you here again about the same time.

Phil.  I will not fail to attend you.

THE THIRD DIALOGUE

Philonous.  Tell me, Hylas, what are the fruits of yesterday’s meditation?  Has it confirmed you in the same mind you were in at parting? or have you since seen cause to change your opinion?

Hylas.  Truly my opinion is that all our opinions are alike vain and uncertain.  What we approve to-day, we condemn to-morrow.  We keep a stir about knowledge, and spend our lives in the pursuit of it, when, alas I we know nothing all the while:  nor do I think it possible for us ever to know anything in this life.  Our faculties are too narrow and too few.  Nature certainly never intended us for speculation.

Phil.  What!  Say you we can know nothing, Hylas?

HYL.  There is not that single thing in the world whereof we can know the real nature, or what it is in itself.

Phil.  Will you tell me I do not really know what fire or water is?

HYL.  You may indeed know that fire appears hot, and water fluid; but this is no more than knowing what sensations are produced in your own mind, upon the application of fire and water to your organs of sense.  Their internal constitution, their true and real nature, you are utterly in the dark as to that.

Phil.  Do I not know this to be a real stone that I stand on, and that which I see before my eyes to be a real tree?

HYL.  Know?  No, it is impossible you or any man alive should know it.  All you know is, that you have such a certain idea or appearance in your own mind.  But what is this to the real tree or stone?  I tell you that colour, figure, and hardness, which you perceive, are not the real natures of those things, or in the least like them.  The same may be said of all other real things, or corporeal substances, which compose the world.  They have none of them anything of themselves, like those sensible qualities by us perceived.  We should not therefore pretend to affirm or know anything of them, as they are in their own nature.

Phil.  But surely, Hylas, I can distinguish gold, for example, from iron:  and how could this be, if I knew not what either truly was?