alan:

Ilkka - I agree with everything you said except for the "still swerving" statement, as specifically applied proactively in the context of modern physics. What you are suggesting is a basic redefinition of what we mean by the swerve, and I would also be for that. The swerve as first formulated by Epicurus (that is, the reason for why there are macroscopic objects and why we have free-will in an otherwise deterministic universe) is not attested to by modern physics. What you are now suggesting we understand the swerve to be is perhaps quantum indeterminacy, or perhaps Brownian motion, or perhaps Heisenberg uncertainty. This is all well and good, but it is not what Epicurus originally had in mind.

Cassius: (to Alan)

"This is all well and good, but it is not what Epicurus originally had in mind." <<< Well, it's probable also that Epicurus had more than one thing in mind when he suggested the theory of the swerve. In apparently making no effort to explain the "mechanism" of the swerve, he was simply stating the effect rather than speculating as to a cause or even really a manner of operation. I am all for further exploration and discussion of possible mechanisms, as I am sure that Epicurus would be -- the point I keep emphasizing is that in engaging in speculation we should never lose site of the big philosophical picture, nor should we open the door in our own minds, or specially in the minds of those who are not trained in the speculative sciences, that we are suggesting that Jehovah or Allah are possible explanations.

I know that you personally are committed to not doing that, but there are many scientists (apparently) who are all too willing to make those connections, and we need to be careful in consideration of our own peace of mind, plus (or more) that of others who are neither equipped nor disposed to deal with these issues. Standing in the theatre and yelling "the atoms are divisible and they are on fire and may explode at any second" would be improper from many perspectives. Of course YOU Alan are not doing that in any way shape or form, but the world got to the mess it is in today in large part because there are so many people who ARE willing to do that, and no debate ever takes place in a totally contextless vacuum.

Ilkka to Alan:

Alan, the swerve is "random movement by a particle". Whatever consequences it has further down the line, it also has a physical definition. I'm sure that Epicurus didn't have any of those things you listed in mind when he formulated the swerve, but that doesn't change the fact that there is random movement. Several different kinds in fact, if I've understood it correctly.

Swerve was an attempt to ground the self evident facts, of compound objects and choice making, in the physical structure of the world. It was the best that could have been done at the time, and something we're still trying to figure out. Maybe we should cut the ancients some slack in matters not settled yet.

Up the line in this thread I promised a cite to a David Sedley article with an interesting description of how Sedley thinks Epicurus came up with the swerve, more from a "Determinism" standpoint rather than simply due to physics theory. Your mileage may vary, but in my experience Sedley is one of the most perceptive commentators on Epicurus alive today. The article is "Epicurus' Refutation of Determinism" and can be found here:

File

Sedley: "Epicurus' Refutation of Determinism"

1983 Paper which is the one of the best treatments of Epicurus' view of the Free Will / Agency / Determinism issue available.

Cassius

June 3, 2020 at 8:40 AM

Alan to Ilkka:

Ilkka I agree with all of that. I only disagree with those who vehemently say that we need the swerve to have agency or even that the swerve of Epicurean atoms really truly exists in the very precise context that Epicurus stipulated them to serve in. You're not saying that, so we don't have a disagreement. The swerve of Epicurean atoms is a very different thing than the random motion of particles in a gas or fluid or the superposition of quantum states or the fundamental inability to register both a particles position and momentum to arbitrary accuracy (all those things that I suggested above that could be considered a 'modern swerve').

Cassius:

"If the elementary particles are quanta, for example, would pleasure cease being the foundation of human morality? I think not." That is a great example of an update in physics that does not change the conclusions an iota. On the other hand, if the elementary particles are found to be inscribed "Best wishes, Jehova" then that would be a scientific discovery that WOULD change the conclusions rather dramatically. As humans we will never see these elementary particles ourselves, so we need a framework for having confidence in our conclusions in the absence of seeing them with our own naked eyes. Are we to say to ourselves, "Yes it's POSSIBLE that they are so inscribed, because I haven't seen them"? I feel confident that even given our advances to date, Epicurus would still say "no." One might want to qualify that with "reasonably possible" or other hedge words, but at some point you're simply playing a word game rather than dealing in useful concepts, because once you truly believe that "anything is possible" then you're a long way toward totally losing touch with human reality.

Philos the reason for my turning this thread into a FAQ is that it is indeed frequently asked in varying forms and will best be found in the future by a title which describes the topic. Were the issue here solely your personal question it would not rise to the level of general interest, and were the issue personal to you and not in need of a FAQ I would not have been able to devote so much extended effort to discussing it with you as I have done. Thanks for posting your comment as that can serve as your caveat that the way the question is phrased was not your intent. That's why I explained in the opening post the nature of the topic I intended to address, on a broader level. I will add to the opening post a note with a link to your comment and I think I can modify it to help with your concern.

We will address some of these issues in the podcast that was recorded today in a way that most should find satisfactory.

To the extent that "some" in Philos' comment refers to me, the point I am making is that physics does not exist alone in its own world. Epicurus confronted in his day, and we confront today, arguments that are based on "words" - "logic" - and that those arguments are of concern to many people. We are always going to be faced with questions that are essentially "You don't know because you haven't personally been there / done that / seen that / etc." It is important to understand how we respond to those questions, what is involved in "waiting," what kind of standards of "certainty" we should expect to hold ourselves to, and what is an appropriate level of skepticism to hold toward various things.

Those who are primarily immersed in scientific pursuits are not generally going to be as concerned with those contentions as those who are not. However in Epicurus' day it was considered a serious philosophic argument to contend that it was impossible to walk across a room, and even today there are all sorts of logical and ontological arguments for the existence of god and similar questions waiting to trap the unwary.

Not everyone needs help in those areas, but there are a lot of people who get concerned with arguments like those who need help in responding. For them, no amount of "physics" is going to be enough.

So when Philos says:

Quote

The Epicurean physics needs to have a modern adjustment, while at the same time not losing any of the most important consequences for the ethics.

I would say that Epicurean philosophy is ultimately not about any particular and precise physics position (and in that I think we are agreed). The issue is more that Epicurean physics were derived using a particular approach to knowledge (the canonical faculties vs "rationalism") and if we don't learn the details of that method then we'll never understand the appropriate consequences for the ethics.

It is very important to observe the resistance that Epicurus displayed toward accepting contentions based on mathematics, geometry, or other aspects of logical modeling. Such conclusions can actually or apparently contradict what we observe through the senses, and that is why we are talking about these issues and need to continue to do so.

Studying the reasoning behind "the swerve," for example, will always be more useful for understanding Epicurus' thought process than it will ever be for explaining the movement of atoms.

The same goes for the infinite universe, life on other words, immutability, indivisibility, and the rest. That is why these issues cannot be dropped as if they were unimportant to talk about.

I'll close this comment by observing that in my ten years of internet involvement in Epicurus, I do see this as a recurring issue. People who approach Epicurus purely from the scientific perspective don't tend to appreciate the "logical" issues. People who approach Epicurus from a "history of philosophy" perspective or an "ethics" perspective don't tend to appreciate the physics of Epicurus and Lucretius, and they hardly spend any time at all on the letters to Herodotus or Pythocles, or on Lucretius' poem.

Both perspectives are important to understanding Epicurus, and we should not let the varying perspectives become at war with one another.

Here is one example that I see of the kind of attitude that is appropriate for an Epicurean to take even when we don't have the amount of evidence we would like to have, as illustrated by what Lucian thought was the proper Epicurean attitude toward a religious imposter, from "Aristotle the Oracle Monger"

And at this point, my dear Celsus, we may, if we will be candid, make some allowance for these Paphlagonians and Pontics; the poor uneducated ‘fat-heads’ might well be taken in when they handled the serpent—a privilege conceded to all who choose—and saw in that dim light its head with the mouth that opened and shut. It was an occasion for a Democritus, nay, for an Epicurus or a Metrodorus, perhaps, a man whose intelligence was steeled
against such assaults by skepticism and insight, one who, if he could not detect the precise imposture, would at any rate have been perfectly certain that, though this escaped him, the whole thing was a lie and an impossibility.

At this point we are branching off in this discussion to a different aspect of this topic: How Supporters of Epicurean Philosophy Should Approach The Effect of Modern Scientific Discoveries

That thread is going to be primarily devoted to "organizational" aspects of how Epicureans should relate to each other and/or incorporate new scientific discoveries in their organized activities.

This thread should continue on the original topic, primarily addressed to individuals in their own studies and thoughts:

To What Extent, If Any, Does Modern Physics Invalidate Epicurean Philosophy?