THE LIFE OF EPICURUS

FROM BOOK X of
DIOGENES LAËRTIUS’
THE LIVES & OPINIONS OF EMINENT PHILOSOPHERS

TRANSLATED BY C.D. YONGE.
 

EPICUREAN EPISTEMOLOGY & PHYSICS

Now in The Canon Epicurus affirms that our sensations and preconceptions and our feelings are the standards of truth; the Epicureans generally make perceptions of mental presentations to be also standards. His own statements are also to be found in the Summary addressed to Herodotus and in the Principal Doctrines.

Every sensation, he says, is devoid of reason and incapable of memory; for neither is it self-caused nor, regarded as having an external cause, can it add anything thereto or take anything therefrom.

Nor is there anything which can refute sensations or convict them of error: one sensation cannot convict another and kindred sensation, for they are equally valid; nor can one sensation refute another which is not kindred but heterogeneous, for the objects which the two senses judge are not the same; nor again can reason refute them, for reason is wholly dependent on sensation; nor can one sense refute another, since we pay equal heed to all. And the reality of separate perceptions guarantees the truth of our senses. But seeing and hearing are just as real as feeling pain.

Hence it is from plain facts that we must start when we draw inferences about the unknown. For all our notions are derived from perceptions, either by actual contact or by analogy, or resemblance, or composition, with some slight aid from reasoning. Even the objects presented to madmen and to people in dreams are true, for they produce effects—i.e. movements in the mind—which that which is unreal never does.

By preconception they mean a sort of apprehension or a right opinion or notion, or universal idea stored in the mind; that is, a recollection of an external object often presented, e.g. Such and such a thing is a man: for no sooner is the word “man” uttered than we think of his shape by an act of preconception, in which the senses take the lead. Thus, the object primarily denoted by every term is then plain and clear. And we should never have started an investigation, unless we had known what it was that we were in search of.

For example: The object standing yonder is a horse or a cow. Before making this judgment, we must at some time or other have known by preconception the shape of a horse or a cow. We should not have given anything a name, if we had not first learnt its form by way of preconception. It follows, then, that preconceptions are clear.

The object of a judgment is derived from something previously clear, by reference to which we frame the proposition, e.g. “How do we know that this is a man?” Opinion they also call conception or assumption, and declare it to be true and false; for it is true if it is subsequently confirmed or if it is not contradicted by evidence, and false if it is not subsequently confirmed or is contradicted by evidence. Hence the introduction of the phrase, “that which awaits” confirmation, e.g. to wait and get close to the tower and then learn what it looks like at close quarters.

They affirm that there are two states of feeling, pleasure and pain, which arise in every animate being, and that the one is favorable and the other hostile to that being, and by their means choice and avoidance are determined; and that there are two kinds of inquiry, the one concerned with things, the other with nothing but words. So much, then, for his division and criterion in their main outline.

But we must return to the letter:

Letter to Herodotus

Such is his epistle on Physics. Next comes the epistle on Celestial Phenomena:

Letter to Pythocles

Such are his views on celestial phenomena.