Frequently Asked Questions

1. Knowledge Of Things That Are Relevant To Us Is Attainable If We Pursue That Knowledge In Ways Consistent With The Nature of The Universe Therefore it is an error to think that knowledge must be based on "forms" or "models" or "ideals" that are held to exist in another reality. This error leads to the belief that the things we experience around us originate from and are to be understood according to those nonexistent "forms." (Plato and others) It is an error to think that knowledge must be based on "essences" that are held to exist as a part within the things we experience around us, This error leads to the belief that the things we experience around us originate and are to be understood according to these nonexistent "essences." (Aristotle and others) It is an error to think that knowledge must be based on divine revelation or by reference to "gods" or "prime movers" who create all things according to their divine will. This error leads to the belief that the things around us originated and are to be understood according to religion. (Judaism, Christianity, and others)

2. Knowledge should be pursued by studying the facts of nature, which means that we must remember that we ourselves, as well as the subject of our knowledge, and our means of considering that knowledge, derive from (1) the eternal properties of the elementary matter, and (2) the temporary qualities of the bodies that are formed by the combinations of elementary matter and void.

3. The Faculties of Observation Provided By Nature Are The Tools By Which We Measure Truth. These are three in number and are collectively referred to as the Epicurean "Canon of Truth." They are (1) the "five senses," (2) the "feeings" of pleasure and pain, and (3) the "anticipations.

4. We should not seek to understand everything equally well, nor should we expect to understand that which is not possible for us to understand. We should seek to have firm convictions about those things which are necessary for our peace of mind. From the Letter to Pythocles: "In the first place, remember that, like everything else, knowledge of celestial phenomena, whether taken along with other things or in isolation, has no other end in view than peace of mind and firm convictions. We do not seek to wrest by force what is impossible, nor to understand all matters equally well, nor make our treatment always as clear as when we discuss human life or explain the principles of physics in general—for instance, that the whole of being consists of bodies and intangible nature, or that the ultimate elements of things are indivisible, or any other proposition which admits only one explanation of the phenomena to be possible."

5. "Reason" and "logic" are not in themselves faculties of observation like the three categories of the Canon of Truth. Diogenes Laertius - Biography of Epicurus: 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.

6. Therefore the opinions derived from "reason" or "logic" must constantly be tested against the data obtained from the canonical faculties. Opinions formed by reason should be concluded to be "true" when clear available evidence supports the conclusion, and no clear evidence contradicts the conclusion. Opinions formed by reason should be concluded to be "false" when clear available evidence contradicts the conclusion, and no clear evidence supports the conclusion. Opinions formed by reason which are not based on data from our faculties of observation, or on which the data from our faculties of observations is unclear, must not be considered "true," but considered "speculative" at best, and we must "wait" for additional evidence before concluding that the assertion is either true or false.

References and additional detail for this list may be found here.

Discussion of this FAQ entry is here.

Epicurus was considered a "dogmatist" because he held that confidence in certain conclusions is possible. Epicurus did not consider it necessary to have omniscience in order to be confident is stating that something can be known. He was very careful, however, to point out the limitations of the senses and the need to verify conclusions and to be open to new facts. Please see the discussion of epistemology in the FAQ here.

From Norman DeWitt's "Epicurus and His Philosophy" Chapter 4: "The Canon, Reason, & Nature"

THE Canon was not an afterthought, as the Stoics asserted,1 but occupied the first place in the triad of Canon, Physics, and Ethics. This arrangement is unalterable, because the Ethics were deduced from the Physics and the truth of both Physics and Ethics was subject to the test of the Canon, which included Sensations, Anticipations, and Feelings.

The task of expounding the Canon would be much simpler were it not for ancient and modern confusions and ambiguities that beset the topic. Epicurus disposed of it in a single roll. The word canon denotes a rule or straightedge but metaphorically includes all the instruments employed by a builder. A perspicuous account of it is presented by Lucretius, who mentions also the square and the plumb line.2 Apart from this passage, however, Lucretius misleads the reader, because he gives exclusive prominence to the Sensations and seems to have lacked a clear understanding of the workings of Anticipations and Feelings as criteria.

These last two criteria, it is manifest, were not discussed in the Big Epitome which Lucretius had before him. In the graded textbooks of Epicurus the topic must have been reserved for advanced students. It is doubtful whether Lucretius was even acquainted with the roll that treated of the Canon. This is unfortunate, because his own one-sided treatment is largely to blame for the classification of Epicurus as an empiricist and for the ascription to him of belief in "the infallibility of sensation."

It is an even worse mistake to have confused the tests of truth with the content of truth, that is, the tools of precision with the stones of the wall. This was the blunder of Pierre Gassendi, who revived the study of Epicurus in the seventeenth century. It was his finding "that there is nothing in the intellect which has not been in the senses." From this position John Locke, in turn, set out as the founder of modern empiricism. Thus a misunderstanding of Epicurus underlies a main trend of modern philosophy. This astonishing fact begets an even greater concern for a correct interpretation, which may cause Locke to appear slightly naive.

The institution of the Canon reflects a contemporary striving for an increase of precision in all the arts, sculpture, architecture, music, and mathematics, but the immediate provocation is to be found in the teachings of Pyrrho the skeptic and of Plato. Pyrrho's rejection of both reason and the sensations as criteria rendered acute the need of establishing a canon of truth. In the judgment of Epicurus Plato also ranked as a skeptic, because he belittled the sensations as undependable and phenomena as deceptive, the only real and eternal existences being the ideas. Thus in his system reason became the only contact between man and reality, and human reason was crippled by the imprisonment of the soul in the body.

Epicurus denied the existence of Platonic ideas on the ground that the only existences were atoms and empty space. Thus to his thinking man stood face to face with physical reality and his sensations constituted the sole contact with this reality. Had he stopped at this point he would have been an empiricist, but he did not. He made room also for a kind of intuition, which is incompatible with empiricism. He postulated that man was equipped in advance by Nature for living in his prospective environment, and not in his physical environment alone but also in his social environment. In addition to the five senses this equipment included innate ideas, such as that of justice, and these ideas, because they existed in advance of experience, were called Anticipations. Moreover, as Epicurus postulated, each experience of the individual, the sensations included, is accompanied by a secondary reaction of pleasure or pain. These pleasures and pains are the Feelings, which also rank as criteria, being Nature's Go and Stop signals.

Thus Nature, having equipped man with a triple contact with his environment, becomes a norm, while the Platonic Reason is eliminated along with the Platonic Ideas. It now remains to explain in more detail the dethronement of Reason and the recognition of Nature as the norm.

Discussion about this answer is here.

What are the central differences that separate Epicurus from other philosophers on the nature of Truth?

Discussion of this question is here.