back to PHL200Y home page

back to course outline


Topic #F51

Epicurus and Lucretius: the physical world

1 February 2002

Scribe: Marcela Crowe


These minutes were not spoken; for another version, go to the spoken minutes



                  Professor Hutchinson began the lecture on Epicureanism by drawing our attention to the fact that throughout the past two lectures, we have examined both the basic elements of the Epicurean physical system - as described by the poetry of Lucretius and also, the general ethical philosophical stances of Epicureanism.  These ethical stances should be viewed as having been drawn from and reinforced by actual physical lessons.


                  After reading from I.951-968 of On the Nature of Things, Hutchinson tells us that Lucretius argues that the universe is necessarily boundless.  Therefore, there exists no fixed point of reference such as the centre or any extremity.  Consequently, nothing within the void can ever be closer to the edge than anything else.  Lucretius infers this point by conducting a thought experiment.


                  Thought experiments have a long history in the development of science.  James R. Brown, a professor at the U of T who gives lectures on, among other things, the Philosophy of Science, has written an excellent book on the subject of thought experiments entitled Laboratory of the Mind.


                  II.968-984, Lucretius presents a scenario wherein someone throws a spear into the direction of the furthest edge of space and asks his readers to hypothesis whether the spear flies on and reaches the end or whether something could prevent the spear from reaching its target.  To choose any one of these options however, would be to neglect the fact that there exists no fixed boundary since the place where the spear began its flight could never itself be at the end of the universe.


                  The idea that the Earth is boundless and consequently, that there exists no absolute grid was met with opposition often for biblical reasons.  Hutchinson is skeptical of the conclusion Lucretius draws from this classical dilemma since Lucretius’ argument rests on the assumption that the universe obeys third dimensional laws of physics.  If however, we are three dimensional beings living in a four dimensional universe, the laws of linear motion with reference to the nature of the universe may not hold true.

This is a very difficult thought experiment to grapple with since the ability to think four dimensionally is a privilege that only a few in this world enjoy.  As it stands, the idea that matter travels infinitely with the impossibility of it stopping does not prove the boundlessness of the universe.  Under the physics of another dimension there exists the possibility that space could be curved.  As a result, an object thrown from a marked point in one direction may end up at the same marker but from its opposite end. 


                  Lucretius’ view of the universe is in contrast with the geocentric ideas of the universe which Plato, Aristotle, Ptolemy and the Stoics supported.  It is not coincidental that those who adopt a geocentric view of the universe are also anthropocentric.  If the cosmos is organized to serve our planet, and if humans are the “greatest” beings on this planet, then, it is no far stretch to suppose that the cosmos also serve man.


                  Indeed, the manner in which one thinks about man’s place in the universe determines many philosophical positions.  For instance, under a geocentric view of the universe it is much easier to maintain that there exists absolute truths and order.  Under Epicureanism however, man is simply lost in this universe with no belief in eternal truths.  Our understanding of our place within the universe has such an effect on us that when the belief that the universe is not created for us is shattered, our consciousness shifts seismically. 


                  Stoics and other philosophers criticize Lucretius’ argument since physical evidence for a non-geocentric world view is not very good.  For instance, Stoics thought the abundance of game on Earth was an example of the generosity of the Gods.  Bedbugs -- as things which ensure that we wake up in the morning -- also have a positive function according to the Stoics.


                  Along with the boundlessness of space, the Epicurean world view also holds that the function of atoms is to fall downward.  In the absence of any obstruction, heavy and light matter fall at the same speed.  In order that this rigorous model of physics does not amount to a constant drizzle of atoms which never interact with one another, the smallest modification of indeterminacy must be added.  Without this modification there is no possibility for creation.


                  A student asked Hutchinson how it is that there could exist downward motion if there was not any upward motion.  Hutchinson informed the class that Epicureans believed that there was in fact downward motion as well as upward motion.  What they did not believe however, was that there exited an absolute bottom or top.  The directions extend infinitely.  Another student then asked whether Epicureans were “plateau-ists” since they thought everything falls downward.  Hutchinson said that they were not.  They did however, reject the notion that everything moves towards the centre.  This view was held by the Stoics and since it is less intuitively obvious than what the Epicureans postulated, the explanation of gravitation did not gain strength until the 17th century with the theories of Galileo and Newton.


                  In relation to what was being discussed prior to the student questions, Hutchinson observed that the principle of indeterminacy was heavily criticized by Cicero.  In fact, Cicero devoted an entire book entitled On Fate, published in the first century B.C.E.  This book distinguishes the terms fixed, fated and determined from one another.  Since the Stoics have a thorough doctrine of the existence of free will and consequently, human responsibility, within a purely deterministic model, Hutchinson wishes to foot note this topic for the later date in which we deal specifically with the Stoics.


                  Epicureans take quite a different stand than the Stoics.  Based on the technique of a subatomic reflection on the theory of human responsibility, Epicureans fail to see how humans can be free if things are entirely determined.  Free will, within the system of the human mind, is found in the wiggle rooms of indeterminacy, so to speak.  These small pockets of indeterminacy allow the individual to change things.  In II.264-271 horses too are attributed with the possession of the impetus to change.  Although, free will comes from more subtle changes within animals, animals nevertheless posses some degree of indeterminacy.


                  The Epicureans were ridiculed for these beliefs; however, interestingly, by the 1930s a physicist by the name of Eddington independently came up with a theory quite akin to Lucretius’.  Using his knowledge of the discoveries made in the 1920s on quantum mechanics and physics, Eddington maintained that the existence of free will can not be reconciled with the Newtonian model of determinacy.  In order to explain free will one must look towards indeterminacies.  Ultimately, Eddington’s theory was not triumphant however, when Hutchinson speaks with physicists about the beginning of the formed universe, he observes that they also talk of chaos and indeterminacy. 


                  Another tenent of the Epicurean atomic theory is that the appearance of reality is deceptive.  From II.309-333, Lucretius relays to us just that.  Looking down from a high mountain, things that are very distinct from each other up close are seen as one and the same.  The questions thus remains for the individual, what would you rather be on a battlefield or a meadow?


                  Hutchinson ended the lecture by reading II.1-62 to illustrate the power and beauty of Lucretius’ poetry.