Accueil
"Even though the senses are our primary point of contact with the world we seek to know, we simultaneously recognize just how easily fallible they are. At one and the same time, we rely on the senses to tell us what is happening around us, to investigate the phenomena we encounter, and to test our understandings of those phenomena, all while knowing that the investigative tool itself is prone to a wide range of illusions and imaginings. Under normal circumstances, however, we do not worry overmuch about the problem. We are happy to acknowledge that our senses are both fallible and limited (compared to those of some animals, for example), but do not find ourselves driven to radical scepticism. So, too, the modern sciences are careful to constrain known channels of perceptual error (including complicated ones like confirmation bias), but, again, the worries do not generally drive scientists to scepticism in the strongest sense. In antiquity, things were not so simple. Given the intellectual climate of the ancient imperial capital, for example, Roman authors encountered scepticism much more immediately.
Fallibility, though, is not the only problem that the senses were seen to pose in antiquity. In Lucretius we find a second epistemological tension with respect to the senses. As is so commonly the case in physics (ancient and modern alike), both the primary evidence for theories as well as the very problem-set of explananda are discovered and examinedby thesenses, and so we findourselves appealing to our eyes and ears as soon as we even begin to talk about what the world is like. At the same time, though, the primary entities about whose existence Lucretius wants to convince us—that is to say, atoms and the void—are by definition not perceptible. This puts Lucretius in a particularly interesting situation, since he needs to use the senses to convince us that what the senses are reporting is not the ultimate truth about the world, but that at the same time those same senses can be used to lead our reason to ‘see’ what is really lying just beneath the surface of those sensory experiences." (pp.131-132)
"Now, it may well be the case that all ancient physics relies to some extent on arguing for the existence of unobservables (we might ask an Aristotelian: if a stick is really made of earth, air, fire, and water, then why can I not see the fire in it right now ?). Atomism, though, is faced with the problem that there are not even ready analogues of its unobservables to point at out in the world at large. Where a Stoic could talk about atmospheric air as being a less refined version of psychic pneuma, or an Aristotelian about fire in a fireplace as being very like elemental fire, the Epicurean is more limited —there is nothing even like microcosmic void to point to, and nothing we see out in the world behaves in any way analogously to the almost (but not quite) propertyless, indivisible atoms of Epicurean physics. To be sure, some things have some properties that are like some aspects of atoms (dust motes flit randomly, rocks are hard), but nothing is really like atoms, and the properties that atoms in themselves do and do not have are more than alittle counter-intuitive when it comes down to it: they move infinitely fast; they move in continuous streams ; they have no colour, temperature, or smell; they cohere and scatter according to rules of their own; they sometimes swerve for no reason at all.
In what follows, I propose to look at how Lucretius handles these tensions that coalesce in the senses, focusing on vision in particular." (pp.132-133)
"The standard Epicurean answer to the problem of the senses was deceptively simple: move the locus of error. Instead of seeing error as a problem of the senses, Epicurus saw it as a problem of judgement. The senses, said Epicurus, were infallible. It was only when the rational agent over-interpreted the information from the senses that error could intrude. Looking at an oar in the water, the eyes faithfully recorded what they saw. But when someone concluded from that visual event that the oar was actually bent —that was where they went wrong. The problem was one of the conclusions reached from the sensory event, not in the sensory event itself (a similar approach was taken by both Ptolemy and Galen in response to sceptical attacks some centuries later)." (p.133)
"But this only shifts the problem. Instead of saying that the senses are fallible so we cannot trust them, the sceptic now simply says that the mind is fallible so we cannot trust what it takes from the senses. Secondly, the problem of how to use the senses to learn about atoms, things unseeable in themselves, still looms. The way around ? Careful delineation of how it is permissible to reason from sensory experience allows us to solve both problems at once. Trained seeing, in the hands of a sufficiently careful philosopher, becomes the key. But the line turns out to be a tricky one to draw, and the traps awaiting the unwary are many.
In this light, if we look at how Lucretius handles vision, we find him working on a number of distinct registers, sometimes pushing the dangers inhering in vision (both epistemological and ethical dangers), sometimes clinging to the reliability of the senses in themselves, and frequently —much more frequently than Epicurus before him— using visual metaphors, allusions, and evidence. In many ways, one might say that vision saturates the poem. Indeed, Lucretius handles vision in ways that are, so far as I can tell, unique among ancient scientific authors." (p.134)
"Almost all the early instances of atoms come bundled with appeals not just to what is or is not visible in the world but also to vision as a sense in itself: we see things in the world that then allow us to ‘see’ that atoms, primordia, underlie everything. Videmus, ‘We see’, he says, ‘the rose come out in spring, corn in the heat, grapes in autumn’ [...] which he takes to show the existence of primordia. So, too, ‘because we see [uidemus] that cultivated is better than uncultivated land, and gives better produce at our hands, it is plain to see [esse uidelicet] that there are the primordia of things in the ground that we summon’ [...] This double coupling of the senses and the two basic existents of atomism (uacuas auris; uidemus primordia) is a subtle but clearly deliberate attempt to tie the truths of atomism always to experience.
And he makes the epistemological point more explicit later in book [...] (‘What can be more certain than these senses of ours, by which we demarcate true and false ?’, Lucr. 1.699–700). Although these words are directed most immediately at Heraclitus, who was so foolish as to say that everything was made of fire when we can see plainly that this cannot be the case, the point is a much larger one: any theory that flies in the face of sensory evidence should be rejected outright. This is not to say, of course, that we will simply ‘see’ the truth about nature as soon as we look at the world—would that it were so simple—but that, with a little help from a trained and focused reason, we can come to learn the proper way of seeing that will make the existence of atoms and the void obvious, palpable, and visible. In order to achieve this, though, we need to ‘see’, in a special, extended sense, one that requires not just the intervention of reason but the imposition of rational seeing on physical seeing. [...]
Nevertheless, as he develops the idea that differing substances possess differing atomic shapes, Lucretius runs directly to the senses as his primary evidence. In particular he offers atomic explanations for why one thing is pleasing to the senses and another painful ; one thing tastes sweet and another bitter. So we recognize (agnoscere) that the shapes of honey atoms are rounder than the barbed atoms of wormwood, which is seen (uideri) to be bitter (Lucr. 2.402–4). Lucretius is careful to cover each sense in turn: taste, sound (whining saws versus melodious harps), smell (burning corpses versus saffron), sight, and touch.
But Lucretius is careful in how he handles sensory evidence. He readily admits that atoms are hidden, even while he uses the language of seeing to show them to us. Thus in his discussion of primary and secondary qualities in book 2, Lucretius often distinguishes between how objects ‘are seen’, uidentur, by us as opposed to how these appearances are in reality caused by the shape or size or arrangement of atoms. And things can have different sensory properties at different times, as a stick in the woodpile versus a stick on the fire. Where an Aristotelian would appeal to potential as an explanation for how the stick could go from inert to fiery, Lucretius talks instead of (atomic) ‘seeds’, semina, which he readily admits are hidden from sight." (pp.135-136)
"We see statues wearing down from years of casual touches; we see the complete dissolution of a host of objects ; we see the composition of things; we see their finitude. We see things of the same size that have different weights. We see storms ; we see reflections in water; and we see the letters of words conjoining to make larger units—all of this just in book 1. [...] Lucretius makes very common use of the idea of not seeing, blindness, which he couches almost always as a moral problem in people. To see the truth, for Lucretius, is to be free of fear and so ethically enlightened ; to be blind is to be immoral or fearful." (p.139)
-Daryn Lehoux, "Seeing and unseeing, seen and unseen", chapter 5 in Daryn Lehoux, A. D. Morrison, Alison Sharrock (eds.), Lucretius. Poetry, Philosophy, Science, Oxford University Press, 2013, 326 pages, pp.131-151.
