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Demokrit, Epikur und Aristoteles über Atome The task is, not so much to see what no one has yet seen; but to think what nobody has yet thought, about that which everybody sees. It is scarcely an exaggeration to say that even in 1900 the only new idea to Leucippus's theory was that each chemical element was identified with a separate atomic species.
Greek 10 Drachma Coin with Democritus of scientists did not believe that atoms exist. Boyle and Boltzmann and others believed this but there was no direct proof. A similar problem we have with Planck's idea of the quantization of energy. How is it possible to derive a quantization from the continuous spectrum of the black body radiation? Leucippus, however, and his disciple Democritus hold that the elements are the Full and the Void--calling the one "what is" and the other "what is not." Of these they identify the full or solid with "what is," and the void or rare with "what is not" (hence they hold that what is not is no less real than what is, because Void is as real as Body); and they say that these are the material causes of things. And just as those who make the underlying substance a unity generate all other things by means of its modifications, assuming rarity and density as first principles of these modifications, so these thinkers hold that the "differences" are the causes of everything else. These differences, they say, are three: shape, arrangement, and position; because they hold that what is differs only in contour, inter-contact, and inclination. (Of these contour means shape, inter-contact arrangement, and inclination position.) Thus, e.g., A differs from N in shape, AN from NA in arrangement, and Z from N in position. As for motion, whence and how it arises in things, they casually ignored this point, very much as the other thinkers did. Such, then, as I say, seems to be the extent of the inquiries which the earlier thinkers made into these two kinds of cause. Aristotle, Metaphysics [985b] Some consider that Democritus used logic arguments for the existence of atoms that if a object can be in principle divided in smaller and smaller parts then it is in principle an objective that is build by objects without magnitude? As Aristotle says: Concerning there being atomic magnitudes. Democritus would appear to be convinced by appropriate, that is, physical arguments, ..., For there is a problem is someone would claim that a body, that is a magnitude, is divisible everywhere and this is possible, then it may be divided at the same time, even if it has not been divided at the same time. And if that were to happen, there would be nothing impossible. Thus, if it is of such kind as to be divisible everywhere - whether in the middle in the same way or in general, when it has been divided, nothing impossible will have happened, since even when it has been divided ten thousand times into ten thousand parts there is nothing impossible, although perhaps no-one would ever divide it so. As body, then, is such divisible everywhere, let it be divided. What will then be left? Magnitude? For that is not possible, for something will not be divided, whereas it was divisible everywhere. However, if there will not be any body or magnitude, and still there will be a division, whether it will consist of points, and there are sizeless things of which it is composed, or there will be nothing at all, so that it would come to be from nothing and be composed of nothing, and the whole would be nothing but appearance. Similarly if is consists of points, it will not be a quantity. For whenever they touched and there was one magnitude, and they were together, they did not make the whole any larger. For when divided into two or more, the whole is not anything smaller, nor larger, than before. There even if all points are put together they will not produce any magnitude.
The idea of atoms is also supported later by Epicurus (about atoms and void, περὶ ἀτόμων καὶ κενοῦ) who studies Democritus theory under Nausiphanes of Teos. His theory is (1) we see that there are bodies in motion, and (2) nothing comes into existence from what does not exist derived from the principle that for everything which occurs there is a reason or explanation for why it occurs, and why this way rather than that (the Principle of Sufficient Reason). The motion implies that there must be empty space i.e. void. Epicurus thinks that macroscopic bodies that we see are are made up of smaller objects which again can are made from smaller objects. However this process of division cannot go on indefinitely, because otherwise bodies would dissolve away into nothing. Peter Prevos discusses problems that have been considered by infinite small and partless atoms: Aristotle argues in book VI of Physics atoms can not touch each other if they are considered to be sizeless. If they would touch each other ‘whole to whole’, the parts would eclipse each other. Sizeless atoms are also unable to touch ‘part to part’ or ‘part to whole’ because they have no parts. Minimal parts themselves are partless, which raises the question whether the theory of minimal parts only moves Aristotle’s problem about contact and succession to another level. Epicurus offers the analogy of perceptible minima as a solution. Epicurus proposes an object that is so far away that it can just be seen. When the object if moved further even the slightest, it would not be visible anymore.1 The minimum size the object appears to the observer is considered to be partless. The observer would not be able to see only part of the object as it would disappear from the field of view. Epicurus’ argument is that sensible minima must be next to one another just as our visual field can be conceived to be composed of perceptible minima. Epicurus argues that sensible minima and minimal parts of atoms are analogous and that the analogy explains how minimal parts can touch each other. Then the question is how can a partless object such as an atom move. The problem stated by Aristotle implies that partless objects either move incidentally to the movement of a larger body or—as described above—we can not state that it is ‘moving’ but only that it ‘has moved’. The latter implies, according to Aristotle, that time consists of a discontinuous succession of partless moments, which in turn implies that motion is staccato as the atom jumps in discrete sections of time and space. Without accelerators just using philosophical arguments and observations such as cutting an apple with a knife Democritus probably “discovered” the atoms. It is possible to think that the atoms were discovered from philosophical first principles only. I think that there are also indirect observations as described before. Today similar problems exist. Theoretical physicists developed models which cannot be tested experimentally. They require accelerators as large as an entire galaxy to achieve the necessary energy. But from time to time some experimental physicists have some idea how experiments can be done that require only limited resources and that are accurate enough to test the theoretical models. The first of them seems to be Democritus. In the first half of the first century BC
). More than 2000 years were required to accept finally the idea of atoms. Even in 1897 Ernst Mach (1838-1916) with kinetic theory of gases theorist Ludwig Boltzmann present at the Imperial Academy of Sciences in Vienna loudly announced: “I don’t believe atoms exist!” 4 Quotes "Epicurus attempted to deal with the contradiction between atoms falling through the void in parallel paths at the same speed and the appearance of novel combinations, or matter, by supposing very slight, chance deviations, or 'clinamen,' in an atom's path. He saw this as analogous to the question of human freedom in a determined nature; i.e., there is no room for ethical considerations. Indeed, "Epicureans saw the development of the world as a random, one-way process" (Toulmin and Goodfield 1965). References Peter Prevos, HELLENISTIC PHILOSOPHY Problems of Atomic Motion in Epicurean Philosophy. 1A.A. Long and D.N. Sedley, The Hellenistic philosophers, Volume 1, (Cambridge University Press, 1987), pp. 37–38. 2The existence of atoms with hooks had been affirmed by Democritus, as we know from the (lost) book of Aristotle On Democritus, a passage of which is reported by Simplicius (In Aristotelis De caelo commentaria) 3Democritus in H. Diels, Die Fragmente der Vorsokratiker, Berlin 1903; VI edition, Kranz Walther ed., Berlin 1951-1952, 3 vols.; reprinted Zürich 1996. 4Lindley, D. 2001. Boltzmann’s Atom: The Great Debate That Launched a Revolution in Physics, The Free Press, New York.
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