Epicureanism Read online

  The parts of animals appear to be functional items in the same sort of way. The heart is not merely a muscle in the chest. It is a pump for blood, allowing the organism to receive nutrients and oxygen. That is why it is made of muscle (instead of bone) and is located in the chest (instead of the left foot). The hand is a grasping implement, and having an opposable thumb allows it to do its job well. Aristotle develops these sorts of functional analyses of bodily parts in the greatest detail. Because of his functional understanding of bodily organs, he would say that a hand detached from a body is not literally a hand (as it cannot do the job that makes a hand a hand), but is called a hand only homonymously; that is, it is a “hand” only in the sense that it is shaped like a hand and used to be a hand (Part. an. I 640b30–641a6).

  The Epicurean response to this line of thought is to deny the analogy between organs and artefacts. The fact that something is useful for the sake of X-ing does not mean that it has the function of X-ing or that it was made in order to X. If I need to drive a tent stake into the ground and forgot to bring along my mallet, I might search around a nearby riverbed for a while until I find a suitably sized rock with a flattened side to do the job. But the flattened rock is not an artefact. It is a coincidence that it has the right size and shape for the task at hand, and its size and shape are entirely the result of non-purposive factors such as erosion by the flowing water of the stream. On the other hand, we did make the mallet in order to do things such as drive in tent stakes, and so features such as its material composition and shape are the result of its function (DRN IV 823–57, LS 13E).

  If our organs had been made by skilled craftsmen gods in order to perform functions such as seeing, pumping blood and grasping things, then the analogy would go through. But as we saw in the previous chapter, the Epicureans argue that the workings of the world are not the result of any sort of divine plan. Aristotle, on the other hand, proposes an immanent teleology. He believes in gods, but does not think that organisms are the result of their plan. Nonetheless, the parts of animals exist for the sake of performing certain functions. But the Epicureans deny that this is possible: in order for something to exist for the sake of some goal, it must be the result of the intention of some agent (Simpl. in Phys. 198b29, IG I-111). To say that the hearts exist in order to pump blood, even though nobody made them for that purpose, makes no sense.

  Natural selection

  The Epicurean reply to Aristotle still leaves open the question of how we can account for the apparent design, the apparent purposiveness, of bodily organs. The Epicureans are right to insist that it does not follow from the fact that something is useful for X-ing that it has the purpose of X-ing. But in the case of the flattened rock, it seems eminently reasonably to assert that it just happens to be useful for the sake of hammering a tent stake, even though it was not made for that end. But to assert that the heart just happens to be useful for pumping blood and the hand for grasping objects appears incredible: it is just too much of a coincidence to accept.

  The Epicureans respond that it is no coincidence that organisms are extremely well adapted for survival and reproduction. The animals and plants we see around today are the descendants of other animals and plants. In the past, there was a much wider variety of organisms around, but creatures with bodily set-ups less well suited for survival and reproduction died off in the competition with others. A creature with its heart located in an extremity would circulate its blood less well, and so it might be sluggish; creatures like us but without opposable thumbs could not handle tools as well as we do and so eventually starved to death; and so forth. Because of this process of natural selection, only the members of the fittest species – those that are adept at survival and reproduction within their ecological niches – are around now. Please note that this is the result of the process of natural selection, but not its goal. Natural selection is not a random process: it proceeds in a definite direction, with less fit organisms being culled over time. But it is not a purposive process either; natural selection is not trying to produce the survival of fitter species any more than a river is trying to produce smoother rocks.

  The affinities of this theory with Darwin’s theory are obvious, but the Epicureans are not evolutionists. Instead, all of the species we see today (plus countless others besides) were all created within a relatively short time. Lucretius is by far our fullest source for the Epicurean story. Long ago, the earth was in a fertile period and was able to act as the “mother” of animals. There was great heat and moisture, and “wombs” grew fastened to the earth, from which new creatures sprang. This probably seems less incredible to the Epicureans than to us, as they believe (along with most other Greeks and Romans) in spontaneous generation. Lucretius appeals to the (supposed) generation of new creatures in muddy warm areas even now – presumably he has worms and the like in mind – to render plausible the idea that the earth did the same sort of thing before (DRN V 772–825). But we do not see large and complicated creatures being hatched directly from the earth, as happened back then, because the earth used to be much more fertile, whereas now it is much colder and drier (DRN V 826–36).

  After this initial bursting forth of new creatures comes the process of natural selection described above. According to Lucretius, many of the creatures were utterly unsuitable to live, lacking feet or hands, while others did not have reproductive organs. These all died out immediately. But later, competition among animals drove other species to extinction, with those having strength (such as lions), cunning (such as foxes) or speed (such as deer) surviving (DRN V 837–77).

  So unlike Darwin, there is no evolution, with new species arising out of old. For Darwin, random mutations can introduce novel modifications to a creature’s descendants, and there is “descent with modification”, with natural selection acting on those progeny, preserving beneficial mutations and eliminating harmful ones. Enough such modifications over time can introduce huge changes, with parakeets descending from dinosaurs and human beings from tree shrews. The Epicureans do seem to accept the idea of some limited Lamarckian evolution. For Lamarck, the characteristics that a creature acquires during its lifetime can be passed on to its descendants, so that giraffes who acquire longer necks by stretching for high leaves will have longer-necked descendants, and Arnold Schwarzenegger will produce more muscular children. Lucretius says that our ancestors were stronger and tougher than we are, because being exposed to the soft living of civilization has caused us to become weaker and less able to withstand extreme conditions (DRN V 925–1027). But there is no suggestion that these changes would be sufficient to make a new species arise.

  The spontaneous generation from the earth of many complex organisms, such as elephants, may seem highly unlikely. The process of abiogenesis (how living things arise from non-living things) is still not understood fully today, but it seems less incredible if the first organisms are fairly simple. The Epicureans could reply that this spontaneous generation need not be likely, it need only be possible. Given the infinity of time and space, if it is possible, it will occur. And once it occurs, it is not at all a coincidence that we happen to live on such a world, one of the tiny fraction of worlds suited to produce complex life like us.

  Still, there are limits on what is physically possible. The Epicurean theory is heavily indebted to a similar theory advanced by the Presocratic philosopher Empedocles, who also asserts that during a fertile period of the world a great variety of misshapen creatures was produced, with this variety subsequently being whittled down. But for Empedocles, some of these primitive creatures were random bodily parts from different types of organisms stuck together, and even individual organs (detached heads and the like).1 Lucretius goes out of his way to argue that such creatures, as well as chimeras, centaurs and the other mixed creatures of mythology, cannot occur. Even spontaneously generated organisms do not come together all at once. Instead, they are the result of a process of biological development, the unfolding of “seeds” within the womb. So they must
meet some minimal threshold of “hanging together” properly to come into existence, even if they are not suitable for surviving or reproducing well. A centaur is a combination of two incompatible types of creatures – man and horse – with different rates of maturation, different nutritional requirements and differing metabolisms. Poorly put-together creatures – people with no limbs, or dogs with no genitalia – are physically possible, but hodge-podge creatures are not, any more than are trees bearing jewels as fruit or rivers running with gold (DRN V 877–924).

  Language

  One phenomenon that the Epicureans need to account for is language. The Epicureans regard language as above all else a biological phenomenon, and they stress the continuities between human language and the sounds instinctively made by other animals. Thus, discussing the Epicurean theory of language at the end of a chapter dealing with their biology makes some sense, whereas for most philosophers this placement would be extremely odd. One welcome consequence of being able to give a biological account of the origins and nature of language is that it allows us to dismiss the superstitious belief that language is a gift of the gods, such as Hermes (Diogenes of Oinoanda 10.2.11 ff., LS 19C).

  However, it appears that there is another way of accounting for language that allows us not to attribute it to the gods, that is, to regard it as a human invention. According to this sort of theory, the names of things are assigned by convention. So, for instance, I want to have a way to refer to “that sort of thing over there”, and I coin the word “dog” to do the job. If our group adopts the name, then the word “dog” means dog for us because of this convention. (Aristotle champions the conventionalist position; see Int. 2.) This sort of theory does not invoke the gods. And as we shall see (Chapter 14), the Epicureans regard justice as a kind of artefact that comes into existence as a result of our adopting a convention about how to behave. So there would seem to be little reason in principle for them not to adopt an analogous position with regard to language.

  Nonetheless, they object to the conventionalist account. Lucretius writes that it would be impossible for us to learn our first words by some person conventionally assigning a name to something. After all, unless the “original namer” had already acquired from somewhere the idea that you can use sounds to name things, he never would have started the practice. And leaving that problem aside, if his audience members did not already have the idea that sounds can express things, his efforts to establish a convention would be utterly unsuccessful; it would be like talking to a deaf crowd, as they would simply be confused and annoyed by his blurting out the senseless sound “dog!” and pointing (DRN V 1041–55).

  Instead, meaningful human language has its origins in animal utterances. Dogs emit one kind of yelp when in pain, another when angry, another when playfully nipping their puppies. Different sorts of impressions – both impressions of external objects (such as a potential sexual partner or a predator) and of internal ones (such as a stinging pain) – naturally evoke different sorts of utterances. This sort of natural language can be found among dogs, birds and horses, and so it is plausible to suppose that the same sort of thing occurred among primitive human beings too (DRN V 1056–90).

  A certain sort of dog yelp “means” pain because it is characteristically caused by the dog’s being in pain. And likewise with the meaning of the other animal utterances (“Lo! A predator”, “Lo! An object of sexual interest”, etc.). So the Epicureans assimilate linguistic meaning to what Paul Grice much later dubs “natural meaning”: the sense in which “smoke means fire” or “spots mean measles”. In the same sort of way, “that kind of yelp means the dog is in pain”. Grice himself sharply distinguishes linguistic meaning from natural meaning, thinking that statements have a “non-natural meaning” that should be analysed in terms of a speaker’s intentions to communicate with an audience (Grice 1957). The Epicureans, of course, do not want to deny that language can be used intentionally to communicate with an audience, but they would be loathe to sharply distinguish the two types of meaning. Instead, our ability to use language to communicate intentionally has its roots in the natural meaning of instinctive animal sounds.

  Likewise, they would not want to sharply distinguish (as do the Stoics) between human language and animal bellows. For the Stoics, our statements express propositions (lekta).2 So when a human being says “I am in pain”, he understands the meaning of the phrase and uses the sentence to express this proposition to somebody. On the other hand, when a dog sharply yelps after being beaten by Descartes with a stick, he expresses his pain but does not state that he is in pain (DL 7.55–6, LS 33H). The Epicureans would admit that there is typically a level of complexity and self-awareness in human speech lacking in dog yelps but deny any radical discontinuity in the sense in which the two are meaningful.

  Although the origins of human language and its meaning can be found in natural utterances that are responses to stimuli, the Epicureans allow that convention plays a large role. Once we have names for things established naturally, then people can extend and refine language. They can agree to new coinages to express things less ambiguously and more concisely, or to name things that previously had no name. In response to the objection that the conventionalist theory is better able to account for the diversity of languages (e.g. even simple natural impressions such as “pain” are designated by wildly different sounds), Epicurus responds that the uncontrived “natural” utterances of primitive peoples could have varied from tribe to tribe depending on their environments and physique (Ep. Hdt. 75–6).

  SEVEN

  The mind

  The mind, a bodily organ

  The Epicureans assert that the mind is a part of the body, no less than a hand or an eye (DRN III 94ff.). Just as the heart is the bodily organ responsible for pumping blood through the body, so too the mind is the bodily organ responsible for sensation, thought and memory (Ep. Hdt. 63).

  The Epicurean theory obviously has affinities to current identity theories of mind, but the physiology is different. Whereas current identity theorists identify the mind with the brain, Epicurus goes along with the view, common (although not universally held) at his time, of locating it in the chest. Lucretius argues for this location by noting that the centre of the chest is where we feel fear, dread and joy; think of the gaping feeling there when you are startled, for instance (DRN III 136–44).1 Likewise, just as mental processes are identified with neural processes by current identity theorists, the Epicureans identify mental processes with atomic processes, for example the raving that accompanies epilepsy occurs because the atoms that constitute the mind are being tossed about like water frothing during a storm (DRN III 487–95). The mind is made up of four different sorts of particles: heat, air, wind and a nameless fourth element (Aëtius 4.3.11, LS 14C, DRN III 231–57). Although they are reticent about the details, the Epicureans do try to explain some mental properties in terms of the properties of these individual elements; for example, heat particles are responsible for the heat of anger, and calm air for tranquillity. The nameless “fourth element” accounts for sensation, and Lucretius says it must be especially small and smooth, to account for the quickness of thought and the ability of the mind to be easily moved by images, which themselves are fine atomic films emitted from the surfaces of objects (DRN III 238–45).

  In addition to the mind proper, there is a mind-like “spirit” (anima in Latin) spread throughout the body, that allows the mind to communicate with the rest of the body: to receive information from the body and to send out impulses to it. If the mind for the Epicureans is like the brain, then the “spirit” is like the secondary nervous system.

  A brief terminological digression: I have been speaking, and shall continue to speak, about the Epicurean views on the mind, usually using “mind” to translate the Greek psyche and Latin animus. I avoid the more common translation of “soul” for psyche, as the English word “soul” currently has connotations that do not apply to the Epicurean views of what the psyche is. For so
me other authors, such as Plato, the translation of psyche as soul is more natural, as Plato argues that the psyche is something immortal and immaterial, which flits from body to body in a cycle of reincarnation, with your conduct in this life determining how well you will do in the next. Aristotle uses the term quite broadly to encompass the organizing principle that distinguishes living from non-living things, so that, for Aristotle, a plant has a psyche without having a mind. For Epicurus, the psyche is the thing that is responsible for functions such as perceiving, thinking and making choices. Saying that the Epicureans believe that the mind is a bodily organ straightforwardly expresses their basic view, whereas saying that they believe that the soul is a bodily organ sounds bizarre, and would unnecessarily muddy the waters.

  The main Epicurean argument for believing that the mind is something bodily is based on the causal interaction of the mind and body, as follows (DRN III 163–87):

  1.

  The mind moves the body and is moved by the body.

  2.

  Only bodies can move and be moved by other bodies.

  * * *

  3.

  Therefore, the mind is a body.

  Actions show that the mind moves the body. I decide to walk to the refrigerator to grab a bite to eat, and lo! my body moves. Another way in which the mind moves the body would be the physiological effects of emotional states, for example the flushing and tightness I sometimes get in my neck when I become upset. Sensations show that the body moves the mind. A swift kick in the shin moves my body, and in turn my body moves my mind as I feel pain: the bodily changes cause a change in my mind.

  The second premise is a bit more contentious. Lucretius says that only bodies can act or be acted on by other bodies because all action and reaction must occur by contact, and that only bodies can touch and be touched (DRN III 161–7). That is, one body can move another by banging into it and pushing it along, and only bodies – which are tangible – can do this sort of thing. Epicurus says that the mind cannot be incorporeal. That is because the only thing that is incorporeal is the void. But the void cannot do or suffer anything; it just allows bodies to pass through it (Ep. Hdt. 67).