Recently there was some discussion of the expanding universe, heat death, the infinite (in time and space) universe and the ramifications of these ideas. I just came across an image from 1750 of the universe comprised of infinite galaxies, which made me think that it might be useful to start a thread on the topic. Just in case anybody would like their mind blown!
Here's the article that the image came from:
Interesting pictures! All I know for sure is that in discussing this we're doing what Epicurus suggested at the end of the letter to Pythocles:
All these things, Pythocles, you must bear in mind; for thus you will escape in most things from superstition and will be enabled to understand what is akin to them. And most of all give yourself up to the study of the beginnings and of infinity and of the things akin to them, and also of the criteria of truth and of the feelings, and of the purpose for which we reason out these things. For these points when they are thoroughly studied will most easily enable you to understand the causes of the details. But those who have not thoroughly taken these things to heart could not rightly study them in themselves, nor have they made their own the reason for observing them.
That picture has an MC Escher vibe to it and also reminds me of the talk of pocket universes. Thanks for starting the thread!
I wanted to go back to the original of Cassius 's underlined quote there:
μάλιστα δὲ σεαυτὸν ἀπόδος εἰς τὴν τῶν ἀρχῶν καὶ ἀπειρίας καὶ τῶν συγγενῶν τούτοις θεωρίαν
This is interesting because it includes θεωρίαν which means "contemplation, consideration." This is the same word used in the characteristics of the sage that gets translated "take joy in public spectacles" but refers to speculation, etc., in the mental sense in Epicurus. So, Epicurus is encouraging Pythokles to most importantly set out yourself on the contemplation of these things.
The word meaning infinite in this list is ἀπειρίας, literally ἀ "un, not" + πειρίας "bounded, limited". Wikipedia had an infinity article which mentions the Greek attitude to the concept. The LSJ had a definition that includes mention of Aristotle and there Stoics use of this concept, so we always have to keep in mind whether Epicurus was using the term on its own or as a reaction to another school.
My take recently was that something doesn't need to be literally infinite for us humans to consider it so. An example is the task of counting of all the grains of sand on every beach and in every desert on Earth. Sure, that's a finite number but for all intents and purposes it might as well be infinite in relation to a human lifespan.
I think we need to be careful, too, about assigning modern mathematical concepts of infinity to classical Greeks. Our scientific notion may be similar but not identical to theirs.
Oh, I forgot to mention the heat death of the universe! For me, this idea makes sense in that the universe would have the same life as everything else. Before the big bang it did not exist, then it existed, and finally it too will die and exist no more. I realize Epicurus said the universe, the All, το παν, always existed. And that may be true from a multiverse perspective, but also, from the perspective of a human lifespan, our own universe might as well be infinite in expanse and time.
My take recently was that something doesn't need to be literally infinite for us humans to consider it so. An example is the task of counting of all the grains of sand on every beach and in every desert on Earth. Sure, that's a finite number but for all intents and purposes it might as well be infinite in relation to a human lifespan.
My personal take is that Epicurus is stressing the need to think about and get comfortable with the idea that there are certain things that are very difficult to get our minds around. He's saying that instead of defaulting to some mystical attitude that "it must be god/divine/magical," we should come to terms with the limits of our capabilities and get comfortable with making decisions within that scope, with is itself a very desirable thing to be good at.
I also think personally there is an important distinction between "uncountable because we don't have the time or ability" (the grains of sand on the beach) vs. "uncountable because it in fact has no limit on the number of instances" (the number of stars or planets or whatever in the universe).
That's why personally for me when we discuss (in the podcasts for example) that it doesn't matter whether the heat death of the universe theory is correct or not, because the time span is too great to be of relevance to us, I personally don't find that a satisfactory place to stop. I don't think Epicurus would have accepted (or suggest that we should entertain) any theory as possible which would postulate that anything could go to nothing, or come from nothing, much less the universe as a whole.
I personally think that the bigger picture argument (will "everything" at some point cease to exist") requires addressing directly. Personally for myself, I am confident that the right answer is "no, the universe will never cease to exist" even though I am not and never will be an expert physicist. At some point the "logical" argument becomes so overwhelming, despite our absolute inability to "be there and experience if for ourselves," that it deserves to be treated as if we are "certain" of it (whatever meaning we assign to "certainty").
So in the end I trace all these issues back together to thinking that Epicurus is asking us to confront the overall general question "How do we take a position when the evidence is less complete than we would like?"
In some cases it is going to be appropriate to "wait" for more evidence, and in some cases it is appropriate to consider ourselves to be "certain" even as we are. One of the major factors in deciding when it's appropriate to wait or not is whether "waiting" would conflict with prior premises that we have accepted with certain. Of course in that case if we are rigorous we would never wait at all or hesitate to pronounce the theory as invalid.
Another factor would be whether the issue is particularly damage-causing, such as opening the possibility of the supernatural, and we also have to consider that we aren't having these discussions in a vacuum among dedicated scientists, but among normal people who will never be specialists, so we need to be concerned about the "practical" effect of theoretical speculation on them. In the end the ultimate goal is NOT "wisdom" or "truth" in the abstract sense (probably a cue there for the nearby "Abstract Ideas" thread).
To me, the issue of studying infinity and similar questions is closely related to the issue of how to think about day to day issues and so its of immediate importance for that reason.
Ha, Don and I crossposted and took opposite positions on the heat death issue 
Well to each his own there, and I think we get a lot out of discussing the issue, because in doing so we get exercise in deciding how much consistency and confidence is appropriate. Does "nothing come from nothing or go to nothing" really mean that, or should be be open to exceptions even there? My perspective is that Epicurus is saying that the evidence before us gives us good reason to be confidence that the principle we are deriving from these observations has no exceptions whatsoever. We then have to deal with the issue that we won't be around long enough to be sure what the "correct" answer is, and so the issue becomes how to apply these rules of thought in the meantime.
For me, this idea makes sense in that the universe would have the same life as everything else.
I think what an everyday ancient Epicurean might say in response to that is that Yes, the rule of having a set lifetime applies to BODIES (of which the Universe as a whole is a big "body" arguably) but the rule does not apply to the elemental particles themselves, which are eternal, never having been created and never being destroyed (or changing at all).
Definitely all component parts of the universe are presumed to always be moving and combining and dissipating and recombining, so that every bodily accumulation of particles has a "date" when it comes together and when it dissipates, so the universe is and always will be a moving and changing "collection" of particles, of which that collection never came from nothing nor will return to nothing.
I gather that's rule number one of Epicurean physics, and the only major "exception" (which really isn't an exception) is that if you master the art of keeping your particles together you might be able to stay that way indefinitely (the Epicurean gods).
Ha, Don and I crossposted and took opposite positions on the heat death issue
Well, there's one way to get honest responses from each of us! 
I think I should expand my thoughts. I'm still not saying "nothing comes from/goes to nothing." As I understand it, if you take the multiverse or pocket universe theory at its word, there is a superstructure within which each universe "pops" into existence. Our universe would "simply" come into being within that larger structure... Just as we "pop" into existence out of the superstructure of atoms and void that make up our universe. There's reason to believe that that superstructure is infinite and eternal and all the universes come into existence, exist and expand, and eventually fade away due to scientific principles. The universes constituent parts would get Incorporated back into the superstructure of the multiverse, like our atoms go back to the universe to be used again somewhere else.
That all may sound spooky and supernatural, but I don't think it is. The more I contemplated how the universe works, the more that line of thought makes sense... It feels right, if you will.
That explanation seems to me a good example of how different people are going to be comfortable with different levels of speculation. I presume that if the theory is that there is a "superstructure" and that "popping" doesn't really mean "from nothing" but rather means that it is somehow generated by the superstructure and "incorporated back into the superstructure," then there's really no violation of the "nothing from nothing" rule which is sort of a logical barrier where the issue is really being fought.
My discomfort with this kind of discussion is that in fact to most common people it does in fact sound "spooky and supernatural" even if it is not intended to be so by the specialists who are theorizing it.
I don't think it is ever appropriate to suggest that there are different "truths" for different types of people on something like this, but I would say that we do need to be aware of the different levels of analysis that people are capable of doing, or maybe said another way, the different perspectives that are in play in which people interpret words at different levels of subtlety.
I'm thinking that Epicurus was perfectly happy to discuss any level of scientific detail himself, but that he also thought it appropriate to reduce things down into broader outlines that most anyone is capable of understanding. "Nothing comes or goes to nothing" is probably such a formulation, useful for most people to keep them away from being manipulated by religion or other types of manipulators, and so it's generally useful to talk in those terms, even if at times it is also appropriate, among experts, to adopt highly-technical definitions of each of the words in the formulation for purposes of scientific theorizing.
So again I think part of this discussion is the issue of context and the purpose of the entire discussion. If we are conducting a seminar of astrophysicists then one way of speaking is appropriate, while if we are talking to the remaining 99% of the people in the world another manner is appropriate. And of course in lumping everyone else into the 99% group, there are huge numbers of subdivisions of categories by language, age, etc, which would be relevant to how to explain things to them.
So maybe this is an issue that involves proper communication as much or more than it does precise scientific theory.
I also don't think we should get caught in the trap of Epicurean Fundamentalism in requiring specifically "atoms and void" to exist as Epicurus described then. And we can't hold Epicurus to modern scientific standards of evidence and terminology.
We know modern "atoms" which make up molecules are not "un-cuttable" now. They're made up of sub-atomic particles according to the Standard Model. And those particles in turn may be made up of "strings" or fluctuations in quantum fields or... And so on.
The ultimate importance of Epicurus's "atoms and void" is that there are fundamental physical "somethings" (atoms) and "something" within which those other "somethings" move (void) that make up the universe... That make up everything. There is no Prime Mover, no Demiurge, no Zeus, no Logos, nothing, other than those fundamental particles/laws/fields/? that comprise the universe and, by virtue of that, we can come to understand the universe without resorting to supernatural explanations, luck, or the vicissitudes of Fortune.
Yes I agree, but just as we have to remain flexible toward ultimate particles we ha e to be at least as flexible and skeptical, or more so, about any particular theoretical model, especially if it is used to imply or advocate interpretations that would undermine the conclusion that the senses (thecanonical faculties) are what human life is all about.
"They're made up of sub-atomic particles according to the Standard Model"
Yes I agree, but just as we have to remain flexible toward ultimate particles we ha e to be at least as flexible and skeptical, or more so, about any particular theoretical model, especially if it is used to imply or advocate interpretations that would undermine the conclusion that the senses (thecanonical faculties) are what human life is all about.
"They're made up of sub-atomic particles according to the Standard Model"
Oh, agreed!
My understanding is that Epicurus built his Philosophy from the ground up, but what was most important in the end was how we live our lives based on that structure with the firm foundation of Canon and Physics.
We can't be beholden to millennia-old texts and be taken seriously when it comes to scientific assertions (like some people .. cough... Say "The Universe is 6,000 years old" ... cough), but being beholden to the spirit of the assertions should not be a problem.
And I also agree that most people don't need to concern themselves with multiverses, quantum field theory, etc., to live their daily lives. For those of us who enjoy that type of contemplation, it's pleasurable. But just knowing there are physical laws in the universe and we're made up of an infinite number of atoms and molecules and building on that, that can be enough.
And I also agree that most people don't need to concern themselves.....
Yes setting the context is a continuing issue. Not only are we constantly dealing with background political issues that are distracting (kind of like Lucretrius), it's always going to be necessary to tune the discussion to the listener so that they can understand it and appreciate it.
Most of us here I would expect are pretty far advanced into the technical and philosophical issues, but I know at least in my own case that I want to be sure to try to reach out to people who might be open to the core issues, but who aren't on the same page in terms of attitude or knowledge toward science, etc.
Ultimately I guess that entails the need to have respect for both approaches and means that any team working together on Epicurean philosophy is going to have a division of labor and a division of approach tailored to the target audience. In the end i don't think that the key issues involve major gray areas that would be a bar to that.
Cassius had some comments above that I wanted to comment on, so I'll include them all here. Most are "Amen, ho adelphos mou (my brother)!" and others I wanted to riff on.
My personal take is that Epicurus is stressing the need to think about and get comfortable with the idea that there are certain things that are very difficult to get our minds around. He's saying that instead of defaulting to some mystical attitude that "it must be god/divine/magical," we should come to terms with the limits of our capabilities and get comfortable with making decisions within that scope, with is itself a very desirable thing to be good at.
Fully agree. It's that "limits" concept again that has a stream running through the philosophy. I also think Epicurus stresses again and again the material nature of reality with no need to default to the supernatural or mystical forces. And agreed that getting comfortable within one's limits is a positive thing, recognizing those limits, but also expanding those limits and one's understanding. Epicurus seemed to encourage students to study the doctrines and expand from the summary/epitome phase to the comprehensive view (i.e., the 37 books of On Nature) while never loosing sight of the summary versions and using those to keep your knowledge fresh *and* using that to be able to explain the philosophy succinctly and clearly.
an important distinction between "uncountable because we don't have the time or ability" (the grains of sand on the beach) vs. "uncountable because it in fact has no limit on the number of instances" (the number of stars or planets or whatever in the universe).
I'm not sure I understand what you're getting at here. I would include the grains of sand, the stars in the sky, and the number of molecules in one's body in that first category. I'm not sure I know what you mean by "instances". And, in fact, all those things are "countable" at least "estimate-able" using extensions of our senses and/or extrapolating using mathematics (e.g., a grain of sand is this big...; planets tend to form around this kind of star and there are this many stars...., etc.). My version of unlimited/infinite comes down to the average humans ability to both count and comprehend these enormous numbers. Which goes back to your point, I believe, about context and what audience one is talking to.
That's why personally for me when we discuss (in the podcasts for example) that it doesn't matter whether the heat death of the universe theory is correct or not, because the time span is too great to be of relevance to us, I personally don't find that a satisfactory place to stop. I don't think Epicurus would have accepted (or suggest that we should entertain) any theory as possible which would postulate that anything could go to nothing, or come from nothing, much less the universe as a whole.
That's not exactly my take - i.e., its being relevant to us - on this topic. Let me expand on my thoughts on this one: I don't think it's a place to stop investigating. And details of all the cosmological theories are still to be worked out! And as I mentioned earlier, that "heat death" is only for our own little "pocket universe". The bigger multiverse stays "here" eternal and unchanging to paraphrase Epicurus. My take on the concept's "relevance" to us humans is that the timespans are SO mind-bendingly huge that - for all intents and purposes - the universe *is* "infinite" in relation to us even though its actual lifespan is (most likely) finite. Scientists have "seen" (with extensions of their senses) space expanding and the broad consensus is that it will keep expanding until the last bit of energy is spent. But that is SO far off in the future - relative to us - that even our far-off descendants or the descendants of the sentient squids that come after us will be long gone. BUT that doesn't negate Epicurus's fundamental Canon and material-based, non-supernatural Physics relative to us with respect to our situation in the here and now.
Also, I should say, I don't necessarily buy the idea of parallel universes where there are infinite numbers of "me" all living slightly different or radically different lives (a la Rick and Morty for those familiar with that animated series). I do find the idea of multiple universes existing side by side in the wider multiverse, all with radically different laws of physics or whatnot, intriguing. As long as there aren't multiple me's roaming around, I can *almost* wrap my head around that.
More to follow... Enjoying this thread! (Does it show? )
Scientists have "seen" (with extensions of their senses) space expanding and the broad consensus is that it will keep expanding until the last bit of energy is spent.
THIS is the point where I have my issue. I think by definition they need to realize and admit and most of all BE CLEAR that what they have seen, as far as they can see, no matter how good the technology gets, is not "the end" of the universe, It's only "the limit of our ability to observe." It still seems to me very clear that we would expect (based on the reasoning that matter and void must both be infinite) that there is indeed no limit to how much matter is out there. So that in fact what probably should be the presumption is that even though "our" universe appears to expanding as far as we can see, we ought to presume (based on the logical arguments) that there is in fact no end, and outside/past our ability to see is additional infinite space with additional cosmos that may or may not be expanding or contracting or whatever in the same way that ours is.
That is why I see a major distinction between the innumerable grains of sand and the infinity of space. If in fact you had the time and inclination and perseverance to could the "grains of sand" on the beach, or on the whole earth, that would seem to be theoretically possible to count and one day come to an end.
With the number of objects in space, however, it would be theoretically impossible to even come to an end in counting, because the best argument is that the universe is infinite in size, and therefore there will always be more to be counted no matter how long one tried.
And at least for me, still shaking off the hold of my religious background, I see a difference in kind between the two situations, and not just a difference in degree. It's coming to terms with the idea that there is no counting EVER the number of elements in the universe that is hard, not coming to terms with the idea of counting the grains of sand on the beach. And it's therefore the problem of infinite space which I would see as the worse enemy in polluting mens' minds with religion, rather than the problem of counting the sand on the beach. The challenge of counting the grains of sand I think could eventually be explained to most "normal" rational people, but the problem of counting something that in fact has no end is where the mind gets tempted toward the supernatural, and that's the temptation that needs to be addressed.
As you say this is an excellent discussion and I am glad we have an open forum where it can be extended in depth.
Right -- so long as the infinite has no boundary, then there's no "other side" for god to live on, and any gods that do exist must live in our own universe. Good point.
It also eliminates any supernatural since everything that exists is subject to natural laws.
From Don: "I do find the idea of multiple universes existing side by side in the wider multiverse, all with radically different laws of physics or whatnot, intriguing."
However universes with different laws of physics might provide an opening for the supernatural. I'm not at all familiar with theories of a multiverse (although I did watch that Spider-Man movie ). Sounds like some challenging reading to tackle!
Right -- so long as the infinite has no boundary, then there's no "other side" for god to live on, and any gods that do exist must live in our own universe. Good point.
Ah! But don't the Epicurean gods live in the intermundia... And couldn't that be the space between the universes of the multiverse? Just throwing that out there.
