Epicurus' Scientific Method

Epicurus' Scientific Method

Elizabeth Asmis
Volume: 42
Copyright Date: 1984
Published by: Cornell University Press
Pages: 386
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  • Book Info
    Epicurus' Scientific Method
    Book Description:

    Elizabeth Asmis describes and analyzes the scientific method and physical theories of the Greek atomist philosopher Epicurus (341-271 B.C.), proposing that Epicurus had a far more coherent and systematic approach to scientific inquiry than most classicists and historians of science have recognized. She argues that Epicurus held that all scientific theories must be inferences drawn from empirical observations and that he adhered to this principle consistently in constructing his own scientific system.

    Epicurus' writings on the principles of scientific investigation have largely been lost, but Asmis attempts to reconstruct them from Epicurus' surviving works and from other relevant sources-including the writings of Philodemus, Lucretius, Cicero, Diogenes Laertius, and Sextus Empiricus. Asmis first studies Epicurus' two rules of scientific investigation-the requirement for initial concepts and the requirement for observation-and reconsiders the meaning of the famous Epicurean claim that all sense perceptions are true. She then shows how Epicurus used his principles of investigation to generate his natural philosophy.

    Her discussion sheds new light on the significance of Epicurus' thought. Epicurus derived his method of inquiry from the early atomists, Asmis concludes, and his philosophy was part of an important empirical tradition-largely overlooked by historians of science-that once was a rival to the scientific methods of Plato and Aristotle. A significant study of Epicurus and of ancient scientific method, this book will interest classicists, philosophers concerned with the history of empiricism, and historians of science.

    eISBN: 978-0-8014-6682-3
    Subjects: Philosophy

Table of Contents

  1. Front Matter
    (pp. 1-4)
  2. Table of Contents
    (pp. 5-8)
  3. Preface
    (pp. 9-14)
    Elizabeth Asmis
  4. Abbreviations
    (pp. 15-16)

    • 1 Epicurus’ First Rule of Inquiry
      (pp. 19-34)

      EPICURUS held that the study of physics begins with the adoption of a method of inquiry. He set out his method in detail in a book Kαvώv, which is not extant.¹ As indicated by the term xαvώv, which denotes a straight rod or ruler and, metaphorically, any type of measure or standard, the book deals with the standards by which investigations are guided.¹ The entire subject was called “canonic” (xαvovixóv).

      Epicurean canonic takes the place of logic as a branch of philosophical inquiry. Epicurus held that logic, as practiced by other philosophers, is of no use to the scientist, and...

    • 2 Rejection of Demonstration and Definition
      (pp. 35-47)

      Epicures demands in his first rule of investigation that the first concepts of investigation “be seen” (βλέπεσυαι) and not require “demonstration” (άπódειξις). Otherwise, he points out, either we would be engaged in an infinite process of demonstration with the result that nothing could be judged, or else we would use empty sounds; in either case, there would be no standard by reference to which a judgment could be made. Epicurus’ argument is clear in general. The first alternative is that we attempt, without ever succeeding, to establish precise meanings; the second is that we use meaningless sounds. To illustrate the...

    • 3 Reference in an Inquiry
      (pp. 48-60)

      INITIAL concepts are required, Epicurus states in his first refer rule of investigation to serve as standards to which we may refer what is believed (or “opined,” doxazómenon), or sought (zhtoumέnon), or perplexing (άpooάύmenon), in order to make a judgment. Diogenes gives an example of how what is “sought” is referred to an initial concept: a thing appears in the distance, and the viewer seeks to know whether it is a horse or a cow. Along with the example, Diogenes points out that we could not seek what we seek unless we had already learned it. Here, what was previously...

    • 4 Formation of Initial Concepts
      (pp. 61-80)

      The preceding chapters have indicated that the initial concepts of scientific investigation are empirically formed As has been noted, this claim is no part of Epicurus’ own first rule of investigation. Epicurus’ statement of this rule contains nothing that a philosopher who proposes to rely wholly on a priori concepts might not accept. Epicurus demands that we have self-evident concepts prior to an investigation to use as standards for the investigation; and to this both empiricist and rationalist philosophers might assent. Not until his second rule of investigation does Epicurus announce what differentiates his method of investigation from that of...


    • 5 Epicurus’ Second Rule of Inquiry
      (pp. 83-103)

      Epicurus’ second rule of inquiry, as stated in the procedural note of the letter to Herodotus immediately after the first rule (quoted on p. 20), is as follows.Again I translate very literally.

      Next, it is necessary to observe all things in accordance with the perceptions [χατά τάς αισυήσεις δεί πάντα τηείν] and simply the present applications [έπιβολάς], whether of the mind or of any of the criteria [χιτηίων], and similarly [in accordance with the affections [πάυη] that obtain, so that we may have the means to infer both what is expected [to appear] [τò ποσμένον] and what is nonapparent [τò...

    • 6 Perceptions: Impact from Outside
      (pp. 104-117)

      The following chapters on perception draw on Epicurus’ own scientific theory of perception to show what evidence the investigator must have in order to make a scientific discovery. Since the theory is itself based on the rule that it is to explain, this may seem a perverse procedure. Epicurus, however, also uses his theory of perception in the Letter to Herodotus to explain and justify his initial demand for a reliance on the perceptions; and this procedure has the explicit approval of the Epicurean Torquatus in Cicero’s On Ends. In pointing out that “unless the nature of things is recognized,...

    • 7 Perceptions: Response by the Organ of Perception
      (pp. 118-140)

      The previous chapter examined how particles enter from outside the perceptual organ to produce perception. The influx of particles from outside, however, is only one of two complementary activities required to produce perception. At the same time as the particles flow into the perceptual organ, the organ responds to the particles by an activity of its own. This chapter examines this activity of the perceptual organ; and the first main source for discussion is Lucretius’ account of thought, or mental perception.

      Lucretius introduces his analysis of mental perception by pointing out that mental presentations are produced by eidola just like...

    • 8 Perception and Opinion
      (pp. 141-166)

      Epicurus made a strict distinction between perception and belief. He sets out this distinction in the Letter to Herodotus; just after the sentence on the form of the solid. Because this sentence is linked closely with the explanation that follows, it is quoted again here. The entire text is as follows:

      And whatever presentation we obtain by application by the mind or [the sight], whether of a form or of its concomitants, this is the form of the solid, generated in accordance with successive compacting or a residue of the eidolon. But falsehood and error always lie in that which...

    • 9 Affections
      (pp. 167-172)

      In his second rule investigation, Epicurus pairs affections (or “feelings,” πάυη)) with the perceptions as providing the a basis of inference concerning what is not observed. I argued in Chapter 5 that although Epicurus recognized the perceptions and affections as joint standards of truth, Epicurus’ followers later subsumed the function of the affections as a standard of truth under that of the perceptions.I also suggested that Epicurus distinguishes between the perceptions and the affections on the ground that the former consist in an awareness of objects external to ourselves and the latter in an awareness of an inner condition. This...


    • 10 The Use of Observations as Signs
      (pp. 175-196)

      Epicurus’ statement of his second rule of investigation has two parts: first, he demands that we have observations in accordance with the perceptions and feelings; and second, he explains why we must have observations of this sort. The preceding section examined the first part of this rule. It now remains to examine Epicurus’ statement that we must observe in the way specified “so that we may have the means to infer [έχωμεν οις σημειωσόμεύα] both what is expected [to appear] [τò ποσμένον] and what is nonapparent [τò άδηλον]."¹ This chapter introduces Epicurus’ method of inference by first presenting a brief...

    • 11 Philodemus: Inference by Similarity
      (pp. 197-211)

      Philodemus is the author of a remarkably well-preserved papyrus roll that was probably titled On Phenomena and Significations (Лεì φαινομένωυ χαì σημειώσεων).¹ The treatise is a compilation of answers to objections directed against the Epicurean method of inference. Most of the answers seem to have originated with the Epicurean Zeno, who headed the Epicurean school toward the beginning of the first century B.C.; others were formulated by the Epicurean Demetrius of Laconia, who was contemporary with or a little older than Zeno.²

      Philodemus’ treatise begins with a series of objections to the Epicurean method of inference, including some criticisms by...

    • 12 The Continuing Debate on Signs
      (pp. 212-224)

      The discussion of signs so far has aimed developments at elucidating in Epicurus’ theory of signs by considering developments in the theory after his time. The problem may also be approached by an examination of the theory and use of signs in the period before Epicurus. Aristotle and earlier writers provide ample evidence of a use of signs that was well developed long before Epicurus’ time. Aristotle is an especially helpful source, because he both analyzes the use of signs in some detail and employs signs himself in support of his theories.

      In the Prior Analytics Aristotle gives the following...


    • 13 Generation and Destruction
      (pp. 227-237)

      According to the preceding discussion, Epicurus proposed an empirical method of investigation that consists in using the phenomena as the facts on which scientific theories are based. This conclusion now needs to be tested by an examination of Epicurus’ own scientific inferences. How closely does Epicurus’ own procedure conform to the rules as they have been analyzed, and in general how consistent and systematic is Epicurus in the way in which he proves his theories?

      The following discussion of Epicurus’ scientific doctrines is divided into two main parts, the first dealing with the fundamental theories of Epicurus’ physics, the second...

    • 14 Bodies and Void
      (pp. 238-260)

      After concluding that the universe is unchanging in what there is, Epicurus undertakes top show that this universe consists of bodies and void:

      consists of bodies and void:

      The universe [τò πάν] is [bodies and a nature without touch] For that there are bodies is witnessed in all cases by perception itself, according to which it is necessary to infer by calculation what is nonapparent, as I said before. If there were not what we call void

      [χενóν] and space [χώαν] and nature without touch [άναφη φύσιν],there would not be anywhere for bodies to be nor [any space] through which...

    • 15 Infinity
      (pp. 261-275)

      The next topic to which Epicurus turns is whether the universe has a limit. He argues as follows that it is unlimited:

      The universe [“all,” τò πάν] is unlimited [άπειον]. For that which is limited [πεπεασμένον] has an edge [άχον]. But an edge is viewed alongside something else. Hence, since it does not have an edge, it does not have a limit [πέας]; and since it does not have a limit, it is unlimited and not limited.¹

      That the universe is unlimited is a conclusion based on the concept of “all,” which was introduced previously, and the newly admitted concepts...

    • 16 Motion
      (pp. 276-290)

      Epicurus concludes his outline of fundamental theories in the Letter to Herodotus with a discussion of the atoms.¹ The claims that he makes here follow upon the previously established claims about the two components of the universe, bodies and void. Epicurus asserts that the atoms move continuously (συνεχώς), either separated a long distance from each other or entangled with other atoms so as to reverberate with them.² Epicurus explains this continuity by pointing out, first, that the void is unable to provide any support, and second, that bodies have solidity, which causes them to rebound after a collision for as...


    • 17 Additional Precision in the Physical Theories
      (pp. 293-320)

      The next two chapters examine to what extent Epicurus uses his two rules of investigation in the more specialized theories that he develops subssequently to his fundamental doctrines. In these theories, Epicurus clearly makes a wide use of empirical proofs. What is unclear is how these proofs agree with the method of inference used in the fundamental doctrines, and in particular how the inductive method of proof is related to the method of reducing a claim to an incompatibility with the phenomena.

      A special problem concerning the more specialized theories is the use of induction to support multiple explanations. In...

    • 18 Multiple Explanations
      (pp. 321-330)

      Toward the end of the Letter to Herodotus and again at the beginning of the Letter to Pythocles, Epicurus draws a distinction between single and multiple explanations. There are certain basic causes, Epicurus claims, that need to be known exactly if we are to be happy; for example, we need to know that the universe consists of bodies and void and that the elementary bodies are atomic. These are single explanations; and here what is unobserved “has a single agreement with the phenomena” (μοναχήνέχει τοīς φαιυομένοις συμφωνίαν).¹ But there are other causes, especially of events in the heavens such as...


    • 19 Summary of Epicurus’ Scientific Method
      (pp. 333-336)

      This study has attempted to show that Epicurus proposed two rules of investigation: a requirement for initial concepts to demarcate the problem, and a requirement for empirical facts to provide a solution. The initial concepts consist in an awareness of empirical facts; and empirical facts are known directly through perception. The two rules together constitute a single method of inquiry, that of inferring what is unobserved on the basis of what is observed. This method was known in antiquity as the method of using the phenomena as signs(σημεīα) of what is unobserved

      The observations that serve as the basis of...

    • 20 The Early Atomists
      (pp. 337-350)

      In the discussion of Epicurus’ physical doctrines, it became apparent that Epicurus was indebted to the early atomists not only for his most basic theories but also for the general method of using the phenomena as signs of what is unobserved. It now remains to test this conclusion by examining the extant evidence concerning the early atomists’ epistemology. This examination is the more important because it has generally been held that the early atomists took the position that the phenomena as such are not real, and that their view of scientific inference was very different from that of Epicurus.


  11. Glossary of Epicurean Terms
    (pp. 351-354)
  12. Bibliography
    (pp. 355-368)
  13. General Index
    (pp. 369-374)
  14. Index of Passages Cited
    (pp. 375-383)
  15. Index of Selected Greek Terms
    (pp. 384-385)
  16. Back Matter
    (pp. 386-386)