§9. The Laughing Philosopher

A convention of scholarship puts Democritus among the pre-S ocratic philosophers, so it is good to remember that he was Plato’s senior contem­porary. Plato’s animosity toward the elder philosopher was legendary.

According to legend, atomism is a Phoenician idea, attributed to Mochus or Moschus, a Sidonian, born before the Trojan War, and possibly identical with the biblical Moses. The first historically attested atomists, Leucippus and Democritus, overcame Eleatic monism by giving Parmenides exactly what he wants multiplied to infinity. Their supposed motivation was to save experience, and especially the experience of change. It is untenable to dis­regard change as grandly as Parmenides did. The fact is, experience cease­lessly changes and philosophers cannot say this is nothing. Change is motion and presupposes an empty place for something to move to, so void must be real. Yet void does not produce change unless it first produces multiplicity—a solitary being in endless void does not change. The annihilating void must penetrate Parmenides's monad and shatter it into a non-decomposable mul­titude. Those are the atoms. They cannot be cut, not because of their small size, but because of their compactness. To divide a thing requires fault lines of internal void, which undecomposable atoms do not have.⁷²

Atoms come in endlessly many shapes and sizes and are in constant mo­tion, which is original, seeming stillness being merely unapparent change.

Greek natural philosophy began with inquiry into causes—the arche of Ionian thought was the ultimate cause, responsible for everything else. That is how these philosophers conceive of causes—as accusations of responsibility. The connotation of all their words for cause (aition and cognates) is legal, from the practice of apportioning blame. Beginning with the medical authors, early natural philosophers depersonalize the legal idea of responsibility. The idea of causally necessary and sufficient conditions emerges in Hippocratic thought, as does the distinction be­tween responsible causes and concomitant or coincidental factors (§3). Democritus is notable for his dedication to causal theories. Ancient biog­raphies emphasize his pursuit of explanations, specifically aitiologia, causal theories. “He would rather discover a single explanation than ac­quire the kingdom of the Persians.” Aristotle reports favorably on his em­bryological research, which included studies of the development of sexual differences, the formation of the embryo, of teeth, and birth defects.

Evidence links Democritus with the medical tradition. Testimonia as­sociate him with his contemporary Hippocrates. Ancient authors refer to (lost) treatises by Democritus on medical topics; for instance, a treatise on elephantiasis, which he alone among ancients investigated. A legend made Hippocrates an apprentice to Democritus. Passages from Democritus touching on medical topics echo contemporary Hippocratic treatises. Compare. for example. Democritus, “Exercise (ponous) that is regularly practiced becomes easier to endure due to habit,” and the Hippocratic Aphorisms: “People who habitually undertake exercise (ponous) cope better, even if they are weak or aged, than strong or young people who are not accustomed to it.”⁷⁵

Democritus is also connected to the medical tradition by association with Pythagoras and his school. An early tradition gives Democritus Pythagorean teachers. He may have been Pythagorean enough to con­sider philosophy in terms of medicine and therapeutics. The alignment between Democritus and the Pythagoreans lies in the link between phys­ical constitution, lifestyle, and ethics. Democritus continued to attract medical followers down to Roman times. The Prognostics of Democritus was a widely circulated Latin manuscript of the early Middle Ages; de­spite the dubious attribution, it evinces Democritus’s reputation for medical knowledge. The Letters of Hippocrates, which are later than the medical texts, relate a story in which Democritus, absorbed in anatom­ical investigations, started to laugh uncontrollably at everything great and small. He so discomfited the people of Abdera, his hometown, that they called in Hippocrates to consult. After a visit he told the people that no physician was needed, the laughing philosopher was fine.⁷⁶

Natural philosophy before Democritus, including the medical authors, tended to assume that opposites struggle with and affect each other.

The aim of his theory of sense perception was to find the real, atomic structure of sensation’s cause and determine the atomic mechanism by which sensation is produced. We have an account of Democritus’s theory in the treatise De sensibus by Theophrastus, Aristotle’s successor at the Lyceum. A scholar observes that of all the theories Theophrastus examines, Democritus’s is closest to Hippocratic ophthalmology, and that his description of the interior of the eye shows the kind of close obser­vation and analysis obtained through dissection or the treatment of eye injuries. Theophrastus says that Democritus postulates a constant stream of atomic effluences, called eidola, thin films of atoms emanating in all directions from all things. These make an impression (emphasis) on the air between a perceptible thing and the organ, which propagates through the air to impress the organ. Here is Democritus’s explanation: “The air be­tween the sight and the thing seen is compacted by the seer and the thing seen and an impression is made on it, as everything is always giving off an effluence.” The air is a drag on radiating eidola, which without it would flow unimpeded over any distance.

Democretian perceptions are effects of the presence of things on our organs. What we learn through sense is how our organs are affected, which is not to know things as they are in themselves. “In fact we know nothing firm, but what changes according to the condition of the body and the things that enter it and come up against it.” Sense qualities (colors, tastes, etc.) are affections of our organs and do not have a nature of their own. “There is no nature belonging to hot or cold, but change in shape [in things] brings about alteration in us.” Sensible qualities are not actual qualities of things, still less of atoms; they are psychical phantasms caused by differences of shape and position in atoms, and depending in part on the atomic conformation of our organs.⁷⁹

Differences in sensory qualities—the difference between hot and cold, say, or different colors—come from differences in atomic shape, the spe­cific mixture of atoms (for nothing is formed of unmixed atoms), the ar­rangement of mixed shapes in the aggregate, and the condition of the perceiver. “Color exists by nomos, sweet by nomos, bitter by nomos.” I think that means these are qualities of appearances, which are always somebody’s appearances, belonging to some tribe or city and subject to the second nature of ethnic difference, which is nomos. Things your people grow up calling sweet are sweet. The ethnography of Herodotus confirmed the divergence of far-flung people in such nomoi. So sensible qualities must not apply to the atoms themselves or to aggregate bodies apart from an ethos of aisthesis.⁸⁰

The power of nomos as second nature is also attested in the Hippocratic Regimen. “Given a proper regimen an individual can become more intelli­gent and shrewder than his nature would like.” Airs, Waters, Places explains that nomos makes Europeans more courageous than Asians because their environments are less uniform, and variation engenders endurance.

Democritus did not deny an unseen reality—no atomist would. Nor did he deny scientific knowledge of nature, for that is what the atom theory is. Knowledge of the insensible or non-evident is for him an inference from sense perceptions treated as signs and subjected to experimental investigation—the semiotic principle introduced by the physiological phi­losopher Alcmaeon. Sextus reports Democritus as holding three criteria:

The criterion for the hidden is appearance (phainomena).

The criterion for inquiry is the concept (ennoia).

The criterion for choice and avoidance is feeling (pathe).⁸²

The criterion of appearance is Democritus’s epistemological principle: ar­rive at knowledge of what is hidden by inference from perceptions used in­strumentally as signs. The second criterion underscores the need for good definitions in research, and the third establishes pathe, affect, affinity or aver­sion, as the last word in choice and avoidance. A fragment reads: “Pleasure and absence of pleasure are the criteria of what is profitable and what is not.” Scholars point out that “criterion” was not a philosophical term of art when Democritus wrote, as it was for Sextus centuries later. But Democritus did refer to a kanon and wrote a book On Kanons, presumably about standards. He says that sensation is a kanon—not the sole one, but one of them, and one without which knowledge of the non-evident is impossible. A fragment carries the title Reply of the Senses to Intellect: “Miserable mind, you get your evidence from us, and do you try to overthrow us? The overthrow will be your downfall.” Nous, the intellectual, rational mind, gets material for know­ledge from the senses, which it clarifies and corrects and thereby attains knowledge of the atomic structure of the world.⁸³

Another fragment differentiates “dark” and “genuine” knowledge.

There are two sorts of knowledge [gnome], one genuine [gnesie], one dark [skotie]. To the latter belong all of the following: sight, hearing, smell, taste, touch. The real is separated from this. When the dark can do no more— neither see more minutely, nor hear, nor smell, nor taste, nor perceive by touch—and a finer investigation is needed, then the genuine comes in as having a tool for distinguishing more finely.

The usual meaning of skotios is dark, dim, or shadowy, though the word was also applied to illegitimate children, who had to be hidden away. What Democritus calls dark knowledge is perception—s eeing, hearing, smell, taste, touch. Genuine knowing knows things too fine for the senses, namely, atoms and void. The senses cannot make discriminations or be a kanon be­yond a certain threshold, when genuine knowledge (the atom theory) takes over. This is not a proto-Platonic opposition between perception and intel­lect. Democritus describes both as knowledge, and their relation is contin­uous. He implies that they work together and that genuine knowledge goes astray without the collaboration of the dusky senses. The senses are imperfect but we cannot say they do not think, and without them we do not think at all. Sense perception is imperfect (“dark”) because with it we apprehend our own affect instead of the distal cause, and because it has natural limits, a threshold of discrimination. So-called genuine knowledge is not more truly knowledge than sensation is, but it is logical, intellectual, not a mindless affect.⁸⁴

I mentioned Democritus’s reputation as a medical author, and Hippocratic authors seemed to approve his ideas. It is difficult to say which way the in­fluence flows, for Democritus and Hippocrates were contemporaries. Both probably learned from each other. Democritus generalizes the Hippocratic concept of disease from body (skenos) to life (bios), and envisions a new sci­ence (sophie) that does for the soul what medicine does for the body. Gregory Vlastos observes that nearly all the normative terms in Democritus, in­cluding metron, harmonia, kairos, and kalon, were used by medical writers to express what conduces to health. Pleasure is a medical sign that a thing agrees with us, the feeling correlated with an unseen but harmonious atomic pattern. “Enjoyment is the landmark,” a fragment Vlastos explains: “Just as the boundary- stone makes visible the actual area within which a piece of pro­perty is located, so pleasure... marks out the area of action which agrees with the well-being of the soul.” Experience, especially the experience of pleasure and pain, also puts a check on ratiocination. The excellence or perfection (teleotes) of the soul corrects the defects of the body by reasoning, that is, by control of the vital motions in accordance with an understanding of what contributes to cheerfulness (euthymie). Wisdom is simply “the prognosis of events without which the stupid can only learn the hard way.”⁸⁵