§17. All Perceptions Are True

By the time of Epicurus, about a generation after Aristotle, the combination of Hippocratic medicine, Democretian natural philosophy, Protagorean criticism, and research at Aristotle’s Lyceum had made experience a phil­osophical concept.

Since atoms are by definition unrelated, all relations are external and con­tingent. But because these relations are real, meaning effective, their molec­ular configurations are also real, with qualities that do not reduce to qualities of isolated atomic constituents. Assemblages have emergent effectiveness. Colors and tastes are physical, natural, not conventional as Democritus said, and the soul has causal powers not reducible to powers of constituent atoms. Nature is an original plurality, originally many and different; not a closed to­tality but a de facto sum that is always changing. We should not misunder­stand the Epicurean axiom that “the totality of things was always such as it is now, and always will be.” The atoms are a given totality, though that may not be as significant as one thinks. If properties of aggregates are just as real and effective as properties of isolated atoms, and the aggregations are ever new and without closure, then so too are the phenomena, so too is nature.¹³⁹

Epicurus is indebted to earlier atomists and Hippocratics not only for his atom theory but also for a method of using phenomena as signs of the un­observed, which he put to use extensively in a natural philosophy that once rivaled that of Plato and Aristotle.

The crucial idea divides nature into the evident and the non-evident, then divides the latter into what can be expected to become evident and what is inherently non-apparent. Phenomena serve as signs of both types of the non- evident. Using terminology that would only fall into place later, phenomenal signs of what can be expected to become evident are called commemora­tive, functioning through our memory of correlated events. Phenomenal signs of what cannot be perceived in any way (e.g., atoms) are called indica­tive signs, indicating what cannot be perceived. Aristotle acknowledges the value of the older empirical method. “It is necessary to use evident things in witness of non-evident things.” Despite relying on this empirical method in his research, his theory of scientific demonstration supplants the method of signs while preserving an empirical starting point for science. Impeccable reasoning led Aristotle unknowingly to advocate for an idea of science that proved sterile. Antiquity and the Middle Ages came and went without one perfect example of a science on this model. Epicurus in antiquity was already unimpressed with Aristotle’s idea of science.

Epicurus assumes that perception discloses real features of the world. He does not logically demonstrate this, but assumes it and uses the resulting evi­dence to explain scientifically why the assumption is sound. This is not point­less, but it is also not what a later age would call an “answer to the skeptic.” That skeptic has not yet been aroused. Empiricism in the Democritus- Epicurus line is not trying to do what Plato and Aristotle tried to do and what later skeptics attack. Skepticism did not attack empiricism; it was empiri­cism, and attacked the rationalistic line of scientific method in the schools of Plato, Aristotle, and the Stoics. What Epicurus expects from sense perception is an argument to rationalize his scientific method. The theory of perception’s cause should support relying on it for knowledge of the unseen. He wants to explain the point plainly so that people understand how science works and why its conclusions are valuable and trustworthy.

The epitome of Epicurean empiricism is the thesis “All perceptions are true.” Taken in their bare givenness, perceptions have an evidence, an enargeia, or force of clarity, that Epicurus explains as the immediate aware­ness of a present object, unbiased by belief or opinion. Perception is an impact from the outside, and comes in six types, the usual five senses plus mental perception or thought (dianoia). These perceptions arise by the im­pact of particles, and in the case of sight and thought the impacting particles are called eidola. Building on the account by Democritus (§9), Epicurean eidola are thin networks of atoms arranged in such a way as to show shape and color. They are outlines much finer than anything that can be seen, released in rapid succession from the surface of solids. These fluxes of eidola stabilize under attention (epiballein) into a perception (phantasia) that can become clear (enarges).¹⁴²

We do not see the eidola; rather it is by their affect that we see bodies.

The external object of perception (the cause of the eidola flow) is one with the phantasia, the perception, or what we see. We see, not the eidola but their cause, whose surface they replicate. Vision is as if we reached out and felt the contours of the surfaces we see, or as if color and shape were tactile quali­ties. Invisible eidola enable a kind of non-local touching: the eidola supply physical continuity, but because they are sub-visible, it looks to us like there is a gap between our eyes and the distal object of vision. Instead of distin­guishing truthful and deceptive presentations, a problem that plagued rival Stoics, Epicurus eliminates the distinction by identifying the external object of perception with the content of perception. That is why perception cannot be untruthful. There is no perceptual object apart from the phantasia, which is the body itself, and therefore no problem about representation or corre­spondence. All perceptions are true because every sense object (aistheton) is in itself as it is for the perception (aisthesis) it causes. It radiates replicas of its surface.

The mind’s own response to perception is an active selection by applica­tion or attention. Though involuntary, it is not passive; the organ engages in an activity of its own, whose outcome is doxa, opinion or belief. This happens automatically and there is no better alternative to opinion. The trick is to become good at judging the opinions we more or less spontaneously form. We should follow only confirmed opinions, or at least those without known counter-confirmation. Opinion about what is yet to appear is verified by “witnessing” and falsified by no witnessing. Whether a figure approaching at a distance is Socrates will become apparent. Opinions about the non­apparent, such as the atomic cause of thunder, are verified by no counter­witnessing and falsified by counter-witnessing.

Sheer sensation (the eidola touch the eye) is not yet cognition, for which we have to name the sensation, and specify its significance. The act of perception in the organ stirs particles of soul in its vicinity, which communicate their ag­itation to adjacent soul particles, until the movement propagates to the cog­nitive center in the heart, where it creates an eidola impress. The impress is useless, however, without a concept to judge it. “Apart from the general con­cept no one can inquire or feel doubt or even hold an opinion, no, nor refute one.” Our first concepts are built up of multiple images like a composite pho­tograph, and are called prolepseis, anticipations, explained as “a concept or stored universal idea, that is, a memory of something often having appeared from without.” Concepts arise with experience, from observation and much memory. “All ideas come from the senses, by encounter, analogy, similarity, and combination, with reasoning contributing something too.” Here is an idea with long legs in empirical philosophy.

Sensations cannot function cognitively until subsumed under concepts, and concepts cannot function cognitively until associated with names, labels by which they can be defined and shared. Epicurus offers an early variation on another empiricist theme already in Hippocratic texts and prominent in modern empiricism with Bacon: the urgency in philosophy for names to have a clearly stipulated denomination. In Epicurus, a mental faculty of doxa performs cognition by assigning sensation to concepts ap­propriately constructed from infallible anticipations. At this stage, no error is possible. Yet people are dangerously eager to make irrational additions, and these are the sources of error. Ordinary thoughtless opinion favors false comparisons, assigning sensations to the wrong concepts, and making con­fusing, even mystifying identifications. Inferences should be accepted only when confirmed by clear perception, and scientific hypotheses about causes in nature have to be tested by reference to such perception. Anticipating the conjecture-and-refutation dialectic of Karl Popper, Epicurus argues that while perfect confirmation (epimarturesis) is impossible, because no deci­sive clear perception avails to check all the way to the end, phenomena might contradict (antimarturein) the hypothesis, which has then to be rejected.

Epicurus applies the atomism of Democritus to an entirely different pur­pose. Democritus wanted causal explanations of natural phenomena, but Epicurus wants to liberate humanity from tyrannical superstition. Socratic tranquility requires us to be as indifferent to nature as the gods are, and Epicurus subordinates natural philosophy to that end, cultivating a philo­sophical indifference to nature that is a condition on happiness. “If we were never troubled by how phenomena in the sky or death might concern us, or by our failures to grasp the limits of pains and desires, we would have no need to study nature.”¹⁴⁵

Epicurus welcomes the power of causal explanations to nullify supersti­tion. The more such explanations we have the better. He welcomes multiple explanations of the same phenomenon, without feeling the need to ask which one is really true. Any explanation that is not contradicted by the phenomena is philosophically acceptable. We are enjoined not to be “so enamored of the method of unique explanations as to groundlessly reject the others.” For in­stance, Epicurus gives six causes for lightning, and says thunder too “can be produced in several different ways—just be sure that myths are kept out of it! And they will be kept out of it if one follows rightly the appearances and takes them as signs ofwhat is unobservable.”¹⁴⁶

Hans Blumenberg writes of the “boundless nonchalance” of Epicurus’s natural philosophy, citing from Karl Marx’s dissertation on ancient atomism. “One can see that he is not at all interested in investigating the real causes of objects. He is merely interested in soothing the explaining subject.” Epicurus was frank about that. “We must not suppose that any other object is to be gained from the knowledge of the phenomena of the sky... than peace of mind and a sure confidence.” Multiple explanations are cheerfully accepted because it does not matter which explanation is true (whatever that means). What matters is there being a causal explanation. The more such explanations, the more likely that there is a causal, natural, non-purposive account, even if we cannot be certain what it is. That cancels the worry that lightning, for in­stance, might be a message (or missile) from the gods. We can relax. Nothing in nature should make us question the Epicurean mantra. The gods do not trouble us, death is nothing to fear.¹⁴⁷