Posts by Cassius

Which is opposed to THIS, which is what Epicurus was fighting against:

From the look of this excellent graphic, this article describes the position taken by Epicurus on the issue of Math vs Reality. It ends with something that sounds consistent with Epicurus to me: "For Abbott, these points and many others that he makes in his paper show that mathematics is not a miraculous discovery that fits reality with incomprehensible regularity. In the end, mathematics is a human invention that is useful, limited, and works about as well as expected."

I am posting this not only for discussion of this article but to ask that if you know of other well-stated articles which take a similar position, that you drop us a link so we can compile a list of reference cites. So if you are aware of others, please post here, and we'll work on more material about this issue in the future.

https://phys.org/news/2013-09-m…tive-world.html

Wow that is quite a video! I have never seen that!

Yep. That remark of his rang a bell with me from the moment I read it some years ago.

Wow - great photos! Thank you Joshua!

Outstanding example, Joshua, thank you!!! And you are channeling DeWitt - who makes almost exactly this same point in his book:

"But this involves a logical sleight-of-hand; it employs an argument by analogy, but argument by analogy only works if things really ARE analogous."

There must be books / articles / citations which help explain this point. Over time I would like to try to find some and this will be a good place to post them.

Sedley is suggesting that in attitude toward logic/dialetic we may have another deviation (watering-down) by later Epicureans. The first two areas were (1) thinking that pleasure has to be defended logically (Torquatus in On ends) and (2) coming up with four criteria of truth instead of Epicurus' three (Diogenes Laertius description of the canon). Sedley is suggesting that Epicurus himself didn't just reject logic/dialectic, he SCORNED it, and that later Epicureans (and therefore presumably us) should not make peace with logic/dialectic at all.......

It gets old to keep saying that everything is "important" - but here is another important passage, confirming how BOTH the Platonists and the Aristotelians were against Epicurus' position.

Here is the section from Lucretius to which Sedley refers in that last quote --

It is hard to overstate the importance of this observation on the Epicurean view of "truth," from the same source:

I see that Sedley would dispute Bailey's word "misleading" in the sentence I quoted above "Logic they reject as misleading...." Sedley thinks the better translation is "Logic they reject as redundant..."

[Usener 376 ]

Cicero Academica II.30.97 (Lucullus): "They will not get Epicurus, who despises and laughs at the whole of dialectic, to admit the validity of a proposition of the form "Hermarchus will either be alive tomorrow or not alive," while dialecticians demand that every disjunctive proposition of the form "either x or not-x" is not only valid but even necessary, See how on his guard the man is whom your friends think slow; for "If," he says, "I admit either of the two to be necessary, it will follow that Hermarchus must either be alive tomorrow or not alive; but as a matter of fact in the nature of things no such necessity exists." Therefore let the dialecticians, that is, Antiochus and the Stoics, do battle with this philosopher, for he overthrows the whole of dialectic."

Norman DeWitt page 172 -

There is a lot of good discussion about these issues in Philodemus' "On Methods of Inference" and the DeLacy commentary on his translation of it https://archive.org/stream/philode…arch/Metrodorus

Poster E:

Logic is a tool, but it is more susceptible to error than correctly executed scientific observation with independent replication. In medicine this is abundantly obvious. Epicurus was not a denialist-- he understood the limits of logic as well as the uses.

I agree that a lot of Epicurus' physics is based on deductive logic -- we can't see atoms so we have to deduce whatever we an know about them.

But as to this sentence "The three axiomata of classical logic (identity, excluded middle, non-contradiction) cannot be challenged by any empirical observation" I am not at all sure that Epicurus would agree, in fact I doubt he would. I believe Epicurus would say that the principals of logic are validated by empirical observations, not the other way around.

Diogenes Laertius (Bailey): "Logic they reject as misleading. For they say it is sufficient for physicists to be guided by what things say of themselves. Thus in The Canon Epicurus says that the tests of truth are the sensations and concepts (Bailey says concepts, most other translators say preconceptions or anticipations) and the feelings; the Epicureans add to these the intuitive apprehensions of the mind. And this he says himself too in the summary addressed to Herodotus and in the Principal Doctrines. For, he says, all sensation is irrational and does not admit of memory; for it is not set in motion by itself, nor when it is set in motion by something else, can it add to it or take from it. Nor is there anything which can refute the sensations. For a similar sensation cannot refute a similar because it is equivalent in validity, nor a dissimilar a dissimilar, for the objects of which they are the criteria are not the same; nor again can reason, for all reason is dependent upon sensations; nor can one sensation refute another, for we attend to them all alike. Again, the fact of apperception confirms the truth of the sensations. And seeing and hearing are as much facts as feeling pain. From this it follows that as regards the imperceptible we must draw inferences from phenomena. For all thoughts have their origin in sensations by means of coincidence and analogy and similarity and combination, reasoning too contributing something."

Poster GFL:

Interesting article!

However we should keep in mind that the main opponent of Plato's idealism was Aristotle. And Aristotle syrongly emphasized the importance of the principle of the excluded middle.

The truth value after perception with our senses is always 0 or 1 and not anything in between. Fuzzy logic applies to probabilities before perceiving something with the senses. But even uncertainty and probability are subject to exact mathematics, not just to vague gut feelings.

Even if one might quote quantum mechanics and quantum superposition as counter-argument, superposition ends at the moment of observation. The wave function collapses and the particle has a well defined state.

The three axiomata of classical logic (identity, excluded middle, non-contradiction) cannot be challenged by any empirical observation. A universe that does not obey these axiomata would not be stable and immediately collapse in itself.

A lot of Epicurus' physics is based on logic, not on empiricism, e.g. the conclusion that the universe is infinite and that the number of possible arrangements of particles is finite. To make Epicurus a denialist of classical logic would do him unjustice.