The Doctrines of Epicurus

XVIII. I will summarize his doctrines quoting 3 of his letters which were the epitome of his philosophy.

1. The letter he wrote to Herodotus, on the subject of Natural Philosophy
2. The one he wrote to Pythocles, which is about the Heavenly Bodies
3. The one addressed to Menœceus, about the discussions about lives.

XIX. He divides philosophy into three parts.

1. The canonical

This serves as an introduction to science. It has one treatise called the Canon.

2. The physical

This embraces the whole range of speculation on subjects of natural philosophy. It has 37 books on nature, and in the letters.

3. The ethical

The ethical contains the discussions on Choice and Avoidance. It is comprised in the books about lives, and in some of the Letters, and in the treatise on the Chief Good.

Accordingly, most people are in the habit of combining the canonical division with the physical. Then they designate the whole under the names of the criterion of the truth, and a discussion on principles, and elements.

They say that the physical division is conversant about production, and destruction, and[435] nature; and that the ethical division has reference to the objects of choice and avoidance, and lives, and the chief good of mankind.

XX. Dialectics they wholly reject as superfluous.

They say that the correspondence of words with things is sufficient for the natural philosopher, so as to enable him to advance with certainty in the study of nature.

In the Canon, Epicurus says that the criteria of truth are:

• the senses
• the preconceptions
• the passions.

But the Epicureans, in general, add the perceptive impressions of the intellect.

And he says the same thing in his Abridgment, which he addresses to Herodotus, and also in his Fundamental Principles.

He says that the senses are devoid of reason. They are unable to receive any impressions of memory. They do not by themselves cause any motion. When they have received any impression from any external cause, then they can add nothing to it, nor can they subtract anything from it.

Moreover, they are out of the reach of any control. One sensation cannot judge of another which resembles itself; for they have all an equal value.

Nor can one judge of another which is different from itself; since their objects are not identical. In a word, one sensation cannot control another, since the effects of all of them influence us equally.

Again, the reason cannot pronounce on the senses; for we have already said that all reasoning has the senses for its foundation. Reality and the evidence of sensation establish the certainty of the senses; for the impressions of sight and hearing are just as real, just as evident, as pain.

Thus, we should judge of things which are obscure by their analogy to those which we perceive directly.

In fact, every notion proceeds from the senses, either directly, or in consequence of some analogy, or proportion, or combination. Reasoning having always a share in these last operations. The visions of insanity and of sleep have a real object, for they act upon us; and that which has no reality can produce no action.

XXI. By preconception, the Epicureans mean a sort of comprehension as it were, or right opinion, or notion, or general idea which exists in us; or, in other words, the recollection of an external object often perceived anteriorly.

Such for instance, is this idea: “Man is a being of such and such a[436] nature.” At the same moment that we utter the word man, we conceive the figure of a man, in virtue of a preconception which we owe to the preceding operations of the senses. Therefore, the first notion which each word awakens in us is a correct one; in fact, we could not seek for anything if we had not previously some notion of it. To enable us to affirm that what we see at a distance is a horse or an ox, we must have some preconception in our minds which makes us acquainted with the form of a horse and an ox. We could not give names to things, if we had not a preliminary notion of what the things were.

XXII. These preconceptions then furnish us with certainty. And with respect to judgments, their certainty depends on our referring them to some previous notion, of itself certain, in virtue of which we affirm such and such a judgment; for instance, “How do we know whether this thing is a man?”

The Epicureans call opinion (δόξα) also supposition (ὑπόληψις). And say that it is at times true, and at times false; for that, if it is supported by testimony, and not contradicted by testimony, then it is true; but if it is not supported by testimony, and is contradicted by testimony, then it is false. On which account they have introduced the expression of “waiting,” as if, before pronouncing that a thing seen is a tower, we must wait till we come near, and learn what it looks like when we are near it.

XXIII. They say that there are two passions, pleasure and pain, which affect everything alive. And that the one is natural, and the other foreign to our nature; with reference to which all objects of choice and avoidance are judged of. They say also, that there are two kinds of investigation; the one about facts, the other about mere words. And this is as far as an elementary sketch can go—their doctrine about division, and about the criterion.