Dialogues Between Hylas and Philonous
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?
HYL. Believe me, Philonous, you can only distinguish between your own ideas. That
yellowness, that weight, and other sensible qualities, think you they are really in the
gold? They are only relative to the senses, and have no absolute existence in nature. And
in pretending to distinguish the species of real things, by the appearances in your mind,
you may perhaps act as wisely as he that should conclude two men were of a different
species, because their clothes were not of the same colour.