I prefer to think of it as Hume's claim rather than Hume's discovery, since "discovery" implies the truth of what's discovered, and I think Hume was wrong, at least on what seems to me the most natural interpretation of what he says in the Treatise of Human Nature. But the interpretation is part of the problem; scholars disagree on what Hume meant. There's a magazine article on this topic, written by one of Hume's defenders, at this link. There's also a recent collection of essays, Hume on Is and Ought (Palgrave Macmillan, 2010), that goes into minute detail on the interpretation and evaluation of Hume's claim.
Not an easy question to take on! This sounds like a question about the USA theatre of debate on gun control and not, say, a question about Great Britain. I will assume a USA context and the debate about background checks, allowing for conceal and carry, and the permissibility of allowing private citizens to have guns that are "military grade" such as an AK-47 or an uzi.
None of the three were pacifists or believed that it was wrong to serve in the Athenian army or navy; Socrates actually served as a foot soldier and was a veteran of the war between Athens and her allies and Sparta and her allies. We have some reason to think Socrates served with distinction. In Plato's version of Socrates' trial (the Apology), Socrates spoke to his judges and the people of Athens to not neglect the care of their souls. This may plausibly be understood as Socrates urging others not to be victims of their own pride, to question their claims to know what is just or holy. Such self-questioning and questioning the convictions of others is only possible under conditions that are pacific or at least non-violent. If you are not safe challenging the "wisdom" of others, your life as a philosopher may be limited and, worse, quite short. So Socrates and his student Plato, and Aristotle (who was Plato's student) had an interest in a culture in which violence (unjustified or tyranical force) is minimal. Based on this, I think the three of them would oppose a heavily armed population with weapons of widely destructive power. So, I suspect they would not want average Athenians to have access to "Greek fire" (a kind of petroleum based weapon that cannot be put out with water, or at least not put out easily). And, if that is right, I suppose they would oppose wide spread possession of military grade weaponry --minimally no shoulder launched anti-aircraft rockets and no machine guns. Also, I think that if they (or we) want a safe context do practice philosophy, we would all want weapons not to be sold to people who have had history of mental illness, violence, a criminal record, and so on. So, while your question is on the verge of being completely impossible to answer (such as asking whether Socrates, Plato, and Aristotle would drive a hybrid), we may be able (very tentatively) to see how their teachings might lead one to support those in the USA who are seeking tighter controls on guns for the sake of public safety. Still, who knows? Maybe they might all three want to join the NRA.
But if you or anyone has read this reply up to now, I will hazard a guess about what Socrates, Plato and Aristotle would do if they found themselves in the USA. I think they might board the next plane to the UK where there is far less gun violence
Your question combines two thoughts about Socrates that are often put together: that he never charged a fee for talking to people, and that (therefore) he was available to everyone. For you describe the panelists as offering themselves "for anyone who wants to ask anyone."
Now, it's true that in some portrayals, especially those written by Xenophon, Socrates equates the non-payment with a spirit of democratic openness. Not charging tuition or other fees means (on this interpretation of Socrates) being free to all. But a fascinating article from nearly thirty years ago, David Blank's "Socratics versus Sophists on Payment for Teaching," challenges this assumption. Blank grants the distinction between Socrates and the sophists on the basis of their charging (high) fees for instruction while he charged nothing. He only questions whether Socrates' purpose was to give his time and effort to all who wanted it.
On the contrary, says Blank, sometimes it appears that Socrates keeps himself free by not charging money. If he were to charge a fee he would be obligated to keep company with the one who paid it. Then it wouldn't be up to him to choose who deserved his company and who did not. What seems very democratic at first in his practice turns out to be an aristocratic attitude, one that holds itself above the vulgar earning of a wage.
So, to get back to your question: Socrates may well applaud the panelists' love of philosophical discourse that keeps them answering the questions people send in. He might only look askance at their democratic desire to send philosophical comments out for all to read. For all his merits, Socrates was a profoundly anti-democratic thinker, and we don't want to paper over that side of him.
As I understand the Republic, the overarching aim of the work is to explain the nature of justice, specifically justice as a quality of individual human beings: in order to elucidate the nature of justice in the individual, Socrates introduces an analogy between justice in the state and justice in the soul. While I believe that Plato not only thinks that there is indeed a close enough similarity between the state and the individual human soul for the analogy between them to be genuinely illuminating, and, moreover, that there must be some relationship between justice in the state and justice in the individual soul if the use of the word 'justice' in both cases is not to be equivocal, I think that the question of whether there is indeed a relevant enough similarity between the state and the soul for the analogy to be fruitful, and, hence, the question of whether it might not be correct to think that justice in an individual is different from justice in the state--neither of which is engaged at any great length by Plato--merit further consideration. So although the argument of the Republic certainly seems to presuppose the aptness of the analogy between the city and the soul, whether their relation is really close enough to support the argumentative weight that the analogy is supposed to bear deserves further attention if one wishes to evaluate the soundness of the argument of the Republic.
I think there are two different issues here, so let me start with the simpler one. Suppose the lecturer said: "To the best of my knowledge—and I've read a great deal on the matter—no one has disproved Kant's claim. That seems the sort of thing one might reasonably be able to say, and might well be what the speaker meant. If so, no problem.
If the speaker is claiming more or less a priori that no one has a disproof, this would be harder to swallow, but there's a way to understand it that makes it not just mere arrogance. Suppose I said: no one has disproved that 3+4 = 7. I might well mean not just that no one happens to have done this, but that no one could do it. And in fact, I'm quite sure that's right: no one could disprove it.
So the speaker might have meant that Kant's claim had a status rather like "3+4=7": necessarily true, hence not disprovable. If so, I'm not sure he's right, but also not sure he's wrong. However, there's yet another possibility. To see it, ask what would count as a disproof of Kant's claim. A proof that it's incoherent would do, but it's hard to believe that it's incoherent even if it's not inconsistent to reject it.
Another sort of disproof would be a counterexample: a case where it was acceptable to violate the maxim. What might that be like?
It's easy to imagine cases where a utilitarian might say we could or even should violate Kant's maxim. The trouble is not that the utilitarian is clearly wrong, but that the counterexample will almost inevitably be controversial, hence not clearly a disproof.
This isn't to say that Kant is right and his opponent wrong; rather it's to suggest that an outright disproof would be very hard to come by. And so I'm inclined to think the speaker might be right.
Good question! There is reason to think that at various points in his life Wittgenstein was very much gripped by religious forms of life. According to McGuinness, during the first world war Wittgenstein was so taken by Tolstoy's The Gospel in Brief that "he read and reread it, and had it always with him, under fire and at all times, and was known by other soldiers as 'the one with the Gospels'." Long after the war he said to O.C. Dury "I am not a religious man but I cannot help seeing every problem from a religious point of view." While Wittgenstein changed his mind on various matters, he seems to have always had a kind of sacred wonder about the world (or existence) itself. In the Tractatus he wrote: "The mystical is not how the world is, but that it is." And later in his 1929 "A Lecture on Ethics" he described the experience of "seeing the world as a miracle." He noted that when he had such wonder at the existence of the world this was "exactly what people were referring to when they said that God created the world." A fine collection of some of Wittgenstein's views are analyzed in a brilliant book: The Rainbow of Experiences, Critical trust, and God" by Kai-Man Kwan. Kwan notes, for example, the times when Wittgenstein seems to explicitly invoke God as a living reality (e.g. "May God enlighten me. I am a worm, but through God I become a man") and at other times when speaking of God and religious forms of life, when Wittgenstein seems to assimilate believing that there is a God to living life a certain way (with humility, wonder, grace). So, the short answer to your question should probably be "we may never know for sure." If he was an atheist, I think we can be confident in thinking he wasn't an atheist for the reasons and in the spirit of Dawkins. And if he was a theist, he was closer to Tolstoy or Austin Farrer (an Anglican priest he admired) or Kierkegaard (whom Wittgenstein admired) rather than John Calvin or Martin Luther. And if agnostic, he might have been rather like the contemporary follower of Wittgenstein Anthony Kenney
You have alighted on an idea that also fascinates me. The quotation is from Thus Spoke Zarathustra, Part IV, section 8. This section is part of a series of fictionalised portraits of exceptional human types (or in some cases, individual persons). Nietzsche is interested in the philosophical significance of certain types of human being. Section 8 is in part a portrait of Jesus. The basic idea is that the the one who has something to give (wealth, assistance, knowledge, whatever) is in a position of power over the one who receives; and the gift itself can serve to reinforce and draw attention to that difference of power. In other words, gifts demean the receiver, perhaps even setting in motion a cycle of revenge. So, how is it possible to be a giver who does not exacerbate the situation of the receiver? How, for example, does the master give to the disciple without forcing the disciple to remain always only a disciple? Please see also Part I, section 22.
I assume there will be non-academic thinkers who are regarded by future generations (or even by others in the current generation) as great philosophers by some. As Aristotle said long ago, honor depends on those who bestow it, and so if enough people think that someone's blog or whatever is loaded with "great philosophy" then so be it. Moreover, I see no reason to think that even some groups of academics will find some the writings (or bloggings) of some non-academic worthy of the title, "great philosophy."
But I also think that we may be talking past one another here. For there are certain fields of philosophy that have become extremely technical, and I regard it as very unlikely that anyone who is not academically trained in these areas will be able to provide important advances in such areas. But of course, there might still come to be some self-taught genius who does just that. So who knows?
I suppose one thing that would be worth thinking more about would be what characteristics make some philosophy or philosopher "great." Speaking just for myself, it is not just obvious that I would call Kierkegaard a "great philosopher." I can't think of anything that I found in his writings that I would regard as "great philosophy," and at least some of it struck me as...well, at best a bit strange. But what do I know?
This is an excellent question. My answer will be controversial; so will any other answer people give you.
But first let's back up. What does "studying Socrates" mean to you? If you are curious about the historical person of Socrates, then you'll want to look into all the historical sources available. More on that in a minute. But if you are interested in the philosophy we mainly associate with Socrates, certain methods of defining vague terms and of understanding the virtues, then it might be enough to read Plato's dialogues for the version of Socrates found in them.
From the point of view of understanding the Socratic philosophy, a lot depends on what one thinks of Xenophon as a philosopher. There are many scholars, and more today than a generation ago, who consider him a subtle, intelligent commentator on political thought and ethics. Many others, however, still find him relatively short on philosophical insight. This is what makes the question controversial. If Xenophon is, as one image of him holds, a simple Athenian aristocrat who missed the deep significance of Socrates (though he did manage to have a lucid, engaging prose style), then he is not the source to consult for Socratic philosophy.
If on the other hand Xenophon possesses hidden depths, and comments on the Athenian intellectual scene more obliquely than people had ever noticed, then the thorough study of Socratic philosophy should bring him together with Plato for a complete picture.
It won't hurt to read through some of the dialogues collected in the "Memorabilia." See if they amplify your understanding of Socrates. If you think there's something going on in the Xenophon, then by all means read further. His dialogues never contain the explicit and detailed philosophical theorizing to be found in such Platonic works as the Phaedo, the Republic, or the Sophist; but they are always worth a look.
Now, suppose your interest is not merely philosophical. You want to know something about Socrates the historical person. All our sources are limited, of course; both Xenophon and Plato give us specific images of Socrates, as produced by sympathetic authors. They are the same age as one another, both of them having been only in their late twenties when Socrates was executed (at the age of seventy), so they also share the same limitation in access to information. To put it simply, Socrates must have been around sixty before either Xenophon or Plato could have met him. Anything about his earlier life they must have learned of secondhand.
There is one source from before them both, but it's a very tricky one: Aristophanes' play "Clouds." Written around 423, when Xenophon and Plato were both children, this is the earliest written reference to Socrates. (It is worth noting that Thucydides, whose "History of the Peloponnesian War" looks exhaustively at Athens from around 430 to 411, two decades of Socrates' maturity, never mentions his name, even though he has much to say about figures like Alcibiades, who was a close friend.) Out of the blue, in 423, Socrates was well known enough to be made the main character of a comedy. In "Clouds" Aristophanes presents a Socrates quite different from the respectable thinker we find in Xenophon or the dialectician in Plato. In the comedy he is something of a trickster, a wily sophist offering atheistical theories of the universe and shrewd tricks for getting out of one's debts.
The "Clouds" is undoubtedly a slander. But it can't be ignored, above all because it is the first appearance of Socrates in the historical record. When you read Aristophanes on Socrates, you must not think this is how he really was; but you should ask yourself what he might have been like to inspire such a caricature.