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Topic #F51

Epicurus and Lucretius: the physical world

1 February 2002
Scribe: Rose Healy


These minutes were spoken on 4 February; for another version, go to the unspoken minutes



We have been talking about two main themes in Epicurean philosophy.  The first is the way Epicurus’ philosophy is transformed into poetry and the second is how Lucretius shapes the physical lessons into moral lessons considering moral explanations for our surroundings.  For this lecture, the focus will be to see how Epicurus’ atomic theories function in his ethical theory.


Thought experiments are an odd way of thinking of an experiment because they are without data or materials.  However, the thought experiment has a long history of importance as our U of T colleague Professor J. R. Brown discusses in his book Laboratory of the Mind.  The thought experiment in Lucretius’ On the Nature of Things is the javelin experiment, which shows the Epicurean idea that there are no fixed places of reference in the universe because there are no boundaries in this infinite space.


In fact, the universe is not bounded in any direction; otherwise it would inevitably have an extremity.  Now, it is plain that nothing can have an extremity, unless there is something on the farther side to bound it, so that there is seen to be a point beyond which our vision cannot trace the abject.  And since we must admit that there is nothing outside the aggregate of things, it has no extremity and therefore has no end or limit.  It makes no difference in which area of it you take up your position, because, no matter what place anyone may occupy, the infinite extent of the universe in every direction is not diminished.

Then again, just suppose that all the existing space were finite, and that someone ran forward to the edge of its farthest border and launched a spear into flight: do you favor the view that the spear, cast with virile vigor, would fly far and reach its target, or do you suppose that something could check it by obstructing its course?  You must grant and adopt one or the other of these hypotheses, and yet both deny you a subterfuge and compel you to acknowledge that the expanse of the universe is infinite.  For whether there is something to check the spear and prevent it from hitting its mark and lodging in its target, or whether it flies on, it did not start from the end of the universe.  In this way I will dog you: wherever you locate the farthest border, I will ask about the ultimate fate of the spear.  Our conclusion will be that nowhere can a boundary be fixed: no escape will ever be found from the limitless possibility of flight. (Book I: 960-982)  


The conclusions of this thought experiment caused much debate especially for biblical reasons because the ideas went against the account of the universe in the Bible.  However, the argument seems to be very good as it is hard to defeat even though it is not an easy thought.   The conclusions of this experiment seem to imply that we can go on a rocket ship for an infinite amount of time and nothing would stop us because of the infinite universe.  We would therefore have an infinite travel time with the permanent idea of not stopping.


The Greek astronomer Ptolemy as well as Plato, Aristotle and the Stoics believed in the geocentric view of the world, the idea that the earth is the centre of the universe.  When one has this geocentric view of the world it is quite easy to follow with an anthropocentric view of life.  If we regard ourselves as being in the middle of everything, our surface is the only surface.  From this, it is easy to conclude that the human rules this surface.  Thus, with the geocentric model, we come to believe that the world was made for the human because we are the centre of everything.


Epicurus rejected the geocentric model because he thought there was no standard grid of reality.  He thought there was no grid in reality and that directions and locations are relative to whomever is using them.  Because there is no standard grid system in our reality it then seems we are lost in reality.  How does this make you feel?  It looks as though one would feel quite different and furthest away from composing an anthropocentric view of reality.  This is much of what our thought is today.  Because we believes ourselves to be a minute part of what is thought to be an infinite universe, it does not seem that we matter very much and are thus lost in reality, causing us to no longer believe in things like eternal truths.  This is a seismic shift from the geocentric and anthropocentric view of reality.  It seems as though our eyes have become opened and we are more self-aware of who we in fact are in relation to all things.


This idea appeared to be crazy to the Stoics and thus they kept up a heavy debate between themselves and the Epicureans on this topic.  The Stoics thought the abundance of the goods available to us was a sign of God’s generosity.  For example, a pig is “fresh meat on legs” and therefore they are great to have in abundance.  In addition, shellfish are also great because they do not walk away when you try to catch them.  The Epicureans would reply to this line of thought by asking what was so great about having bed bugs?  Some Stoics actually replied to this that bed bugs help us get up out of bed in the morning.


The Epicurean theory that reality is relative was a part of their cosmological worldview as well.  They thought that in this universe there are zones where atoms fall.  In these zones there is a certain degree of indeterminacy found in the smallest modification.   From these small modifications of indeterminacy, new systems are formed and it is here that free will is developed.


A student then asked:  If there is no down and bottom, how can atoms fall down?

Professor Hutchinson then said that the Epicureans did say there is a down.  There is no absolute direction but there is a down.  It was the Stoics who thought everything falls to the middle, while the Epicureans though everything falls downward.  The explanation of gravity was the missing part of this theory, all the way up to Galilean thought.


There was quite a degree of controversy over the Epicurean idea of indeterminacy.  Cicero particularly criticized Epicurus quite a bit over this idea.  Cicero integrated three strands of thought into his philosophy to argue against Epicurus.  These strands were what was fixed, fate and determined features of determinacy.


Epicurus went on with this idea to say that it is evident that our bodies are constantly changing.  In the material system of our bodies there are many seeds of indeterminacy, which allow the state of the body to be changing always.  Thus, he set up the indeterminacy of atoms as the reason for the possibility of self-generated change in animate material bodies. 


Epicurus was very much ridiculed for his thought on indeterminacy.  However, a 20th century scientist named Eddington independently came up with the same idea.  He said that our free will is hard to reconcile with when we have a mechanical model of reality.  He thought that there were indeterminacies in reality and it was these indeterminacies that were then able to form relationships to produce freedom in bodies.  It was Quantum Mechanics that led to solving the problem of free will according to some.  However this is not a view held by many scientist and philosophers today because in fact it does not really seem to work.  Therefore, this theory ended up not being a very great triumph.


What needs to be mentioned is Lucretius’ use of metaphor in book II of On the Nature of Things.  The evident ones were the metaphors of war and of calm plains, which are obviously opposing pictures of reality.


All the ultimate particles lie far beneath the range of our senses.  Since they themselves are imperceptible to you, their movements too must be hidden from sight--an inference confirmed by the fact that even perceptible objects often conceal their movements when they are separated from us by a wide space.  Often on a hillside fleecy sheep crop the luxuriant pasture and inch forward wherever the tempting grass, pearled with fresh dew, summons them, while their lambs, replete with food, gambol and gently butt.  Yet to us in the distance the whole scene seems indistinct, appearing only as a motionless white blur on the green of the hill.  Again, great legions fill a spacious plain with rapid movement in vigorous imitation of war: the glitter of arms glances the sky, as the earth on every side reflects the gleam of bronze; the ground resounds to the tramp of strong men’s feet; shouting strikes the mountains and re-echoes to the starry firmament; cavalry gallop round the flanks and suddenly career through the center, making the plain tremble beneath the vigor of their charge.  And yet high in the mountains there is a spot from which all seems to be stationary, appearing only as a motionless pool of bright light upon the plain.  (Book II: 310-332)


In addition to that passage, there is another where Lucretius uses the metaphor of battle to show how much our life is a struggle.


It is comforting, when the winds are whipping up the waters of the vast sea, to watch from land the severe trials of another person: not that anyone’s distress is a cause of agreeable pleasure; but it is comforting to see from what troubles you yourself are exempt.  It is comforting also to witness mighty clashes of warriors embattled on the plains, when you have no share in the danger.  But nothing is more blissful than to occupy the heights effectively fortified by the teaching of the wise, tranquil sanctuaries from which you can look down upon others and see them wandering everywhere in their random search for the way of life, competing for intellectual eminence, disputing about rank, and striving night and day with prodigious effort to scale the summit of wealth and to secure power.  O minds of mortals, blighted by your blindness!  Amid what deep darkness and daunting dangers life’s little day is passed!  To think that you should fail to see that nature importantly demands only that the body may be rid of pain, and that the mind, divorced from anxiety and fear, may enjoy a feeling of contentment!

And so we see that the nature of the body is such that it needs few things, namely those that banish pain and, in so doing, succeed in bestowing pleasures in plenty.  Even if the halls contain no golden figures of youths, clasping flaring torches in their right hands to supply light for banquets after dark, even if the house lacks the luster of silver and the glitter of gold, even if no gold-fretted ceiling rings to the sound of the lyre, those who follow their true nature never feel cheated of enjoyment when they lie in friendly company on velvety turf near a running brook beneath the branches of a tall tree and provide their bodies with simple but agreeable refreshment, especially when the weather smiles and the season of the year spangles the green grass with flowers.  Fiery fevers quit your body no quicker, if you toss in embroidered attire of blushing crimson, than if you must lie sick in a common garment. 

Therefore, since neither riches nor rank nor the pomp of power have any beneficial effect upon our bodies, we must assume that they are equally useless to our minds.  Or when you watch your legions swarming over the spacious Plain in vigorous imitation of war, reinforced with numerous reserves and powerful cavalry, uniform in their armor, uniform in their spirit, can it be that these experiences strike terror into your irrational notions, causing them to flee in panic from your mind?  Can it be that the fears of death leave your breast undisturbed and eased of care?  But if we recognize that these suppositions are absurd and ridiculous, because in reality people’s fears and the cares at their back dread neither the din of arms nor the cruel darts, and strut boldly among kings and potentates, respecting neither the glitter of gold nor the brilliant luster of purple raiment, how can you doubt that philosophy alone possesses the power to resist them?  All the more so, because life is one long struggle in gloom.  For, just as children tremble and fear everything in blinding darkness, so we even in daylight sometimes dread things that are no more terrible than the imaginary dangers that cause children to quake in the dark.  This terrifying darkness that enshrouds the mind must be dispelled not by the sun’s rays and the dazzling darts of day, but by study of the superficial and underlying principle of nature. (Book II: 1-61)