The Way We Know
And he taught us that unless, at the very first, we have confidence in our senses as to those things which are clear and apparent to us, there will be nothing to which we can appeal when we seek to prove, by reasoning of the mind, anything about those things which are hidden. (Lucretius Book 1, line 420) -5
Thus the wise man will hold firmly to that which is true, and he will not be a mere skeptic. [(Diogenes Laertius, Book X)]
Yet there are some men who will claim that nothing at all can be known. As for these, they know not whether even their own claim can be known, since they admit that they know nothing. [(Lucretius Book 4)]
We therefore decline to argue with men who place their head where their feet should be. And yet, even if we granted their claim that they know nothing, we would still ask these questions: [(Lucretius Book 4)]
Since they have never yet seen any truth in any thing, how do they know what "knowing" and "not knowing" are? What is it that has produced in them this knowledge of the true and the false? What is it that has proved to them the difference between the doubtful and the certain? [(Lucretius Book 4)]
That which is able to refute the false must by nature be provable with a higher certainty to be true. And what can fairly be accounted of higher certainty than sensation? [(Lucretius Book 4)]
Can reasoning alone contradict the senses, when reasoning itself is wholly founded on the senses? If the senses are not true, all reasoning is rendered false as well. [(Lucretius Book 4)]
So if by reasoning you are unable to explain why a thing close at hand appears square, but at a distance appears round, it is far better for you to state that you do not know the reason, rather than to let slip from your grasp your confidence in sensing those things that are clear. [(Lucretius Book 4)]
For if you lose your confidence in your senses, you will ruin the groundwork and foundation on which all of your life and existence rest. [(Lucretius Book 4)]
Not only would reason collapse, but life itself would fall to the ground, were you to lose confidence in your senses and fail to use them to shun those pitfalls in life which must be avoided. [(Lucretius Book 4)]
Just as when you erect a building, if your ruler is crooked, your square is untrue, and your level is sloped, then your construction will be faulty, without symmetry, and leaning, with its parts disposed to fall - all ruined by the first erroneous measurements. [(Lucretius Book 4)]
So too will all your efforts at reasoning about things be distorted and false if the sensations on which your reasoning is based are unreliable. [(Lucretius Book 4)]
Therefore, as we reason, we must grasp firmly the ideas which we attach to words, so that we may thereafter be able to refer to those words with confidence, and not leave everything uncertain, or go on explaining to infinity with words devoid of meaning. [(Epicurus, Letter to Herodotus)]
Thus while we direct our greatest and highest interests by reason throughout our whole life, we do not rely either on dialectical reason or logic as our ultimate Canon of Truth. [(Epicurus Doctrine 16, Epicurus' Letter to Herodotus, Diogenes Laertius Book 10)]
Instead, the faculties which constitute our Canon of Truth are our senses, our preconceptions, and our feelings of pleasure and pain, for it is by means of these that we test those things which are true, and we determine which are obscure and need confirmation. [(Epicurus' Letter to Herodotus)]
For only when those things which are clear to us are understood is it time to consider those things which are obscure. [(Epicurus' Letter to Herodotus)]
Now, apply your mind, for a new question struggles earnestly to gain your ears, a new aspect of things is about to display itself. [(Lucretius Book 2)]
Do not be dismayed by the novelty of my words: weigh these matters with keen judgment, and if they seem to you to be true, embrace them, or if they be false, gird yourself to battle them. [(Lucretius Book 2)]
Just as dogs discover by smell the lair of a wild beast that is covered over with leaves, you, by yourself alone, must learn to see one thing after another, and find your way into dark corners to draw forth the truth. [(Lucretius Book 1)]
Think carefully on these things, and then, one step after another, the true path will grow clear. Not even the darkest night will rob you of the road, for each step will light the torch for the next. [(Lucretius Book 1)]