I will confess that I don't see the charm of Tegmark's view. I quite literally find it unintelligible, and I find the "advantages" not to be advantages at all. You suggest a few possible attractions of the view. One is that "atomic and subatomic particles have only mathematical properties (mass, spin, wavelength, etc.) and hence we might as well see them as nothing but math. Any proton, for example, is quite interchangeable with any other." But first, the fact that we only have mathematical characterizations of these properties is both false and irrelevant insofar as it's true. It's false because knowing something about the mass or the spin or whatever of a particle has experimental consequences. It tells us that one thing rather than another will happen in real time in a real lab. If that weren't true, we'd have no reason to take theories that talk about these things seriously; we'd cheat ourselves of any possible evidence. Of course, we may not know what spin is "in itself," and perhaps to that...

I think there may some some false dichotomies afoot here. Most of us think there are some first-order moral facts. For example: I may think (I do, actually) that torturing people just for fun is wrong. However, if I'm doing moral philosophy, I'm not trying to assemble a collection of first-order moral truths. I'm trying to present an account of (for instance) what makes things right or wrong. And so I offer some general view—for example, some version of utilitarianism, perhaps. But how do we decide whether my theory is correct? What counts as evidence? One important piece of evidence is whether my theory can account for uncontroversial cases. I think it's pretty uncontroversial that torturing people for fun is wrong. If my theory didn't entail this, that would be a serious piece of evidence against it. (Compare: if a scientific theory fails to account for some apparently unproblematic piece of experimental evidence, that's a strike against the theory.) Part of the process of arriving at reflective...

That's certainly one acceptable response. Others might include voting for a third candidate if one is available, writing in a candidate's name if the ballot allows, or, in extremis , spoiling the ballot as a protest. There's another issue worth raising. One might ask whether one's dislike of a candidate stands up to scrutiny. In this Presidential election, many people claim that they dislike both major party candidates. But a couple of things to bear in mind. 1) Personal dislike, as in "I find him/her obnoxious" doesn't strike me as a very good reason to vote against someone, especially if there's a lot at stake. What one might more reasonably care about is whether the politician favors policies that one find acceptable, and whether s/he will be effective at promoting them—whether or not s/he is someone whom you find obnoxious. Is what you find obnoxious just a matter of personality? Or is it a symptom of something that matters for larger reasons? 2) Is the dislike based on good information? Here I...

An interesting case! My reaction is that the attitude you describe isn't incoherent or confused, but isn't noble or wise either. Just to review: in the case you've described, the cyclist is negligent, ends up dead because of that, and someone (the driver) who did nothing wrong becomes the unwitting instrument of the person's death. If the driver had happened along a second earlier, she might have been able to swerve and avoid hitting the cyclist. If a police officer had been there, the cyclist might well have gotten a ticket. We hold people responsible for being negligent, and depending on the consequences of their negligence, the responsibility might be extensive. And so it's not confused to say that the cyclist is to be blamed if anyone is. It's also not confused to say that in addition to his own death, the cyclist's negligence had the effect of leaving an otherwise innocent person with a tremendous psychological burden. But what do we do with all those thoughts? If the driver was distraught,...

Think about water. When a lexicographer asks what the word "water" means, s/he is asking how the word is used. It's an empirical question about people's actual linguistic behavior. If it turned out that enough people use the word "water" to refer to vodka, then "vodka" would be one of the meanings of the word "water." But when a chemist answers the question "What is water?", s/he's not telling us how the word is used. On the contrary, s/he will assume that that's settled. The question isn't about the word; it's about the stuff that we use the word to refer to. What is it? And, at least close enough for present purposes, the substance that we refer to by using the word "water" is the liquid composed (mostly) of molecules of H2O. The chemist's answer can be quite different from the lexicographer's. A lexicographer could have come up with a perfectly acceptable account of the meaning-in-use of the word "water" before we knew what water is. Many people who use the word "water" correctly don't know...

I think the way to sort this out is to be careful about some relevant distinctions. A theory is a certain sort of construction that we use for prediction/explanation etc. Theories are at different levels. A biological theory or a psychological theory is at a quite different level than a theory of subatomic particles. Furthermore the laws or generalizations we use in biological or psychological explanation will by and large not appeal to the concepts we use in our physics. If we try to define biological or psychological concepts in the vocabulary of physics, we're not likely to succeed, and even if we did, it's not likely that this would be a useful way to do biology or psychology. So theories in biology and psychology don't reduce to theories in physics if by "reduce" we have in mind deriving the higher-level laws from physical laws and facts, couched in the language of physics (together with so-called "bridge principles" to connect the two vocabularies.) That said... It may still be that...

Consider two people who join the military. Person A's motive is socio-economic advancement. Joining the military seems the best path to a good career. But s/he also accepts the country's values, thinks the country needs a military, and thinks that being in the military is an honorable profession. S/he would not join the military of any other country that might possibly be unfriendly to her/his own country. Person A's motive is likewise socio-economic advancement. S/he doesn't care about the country's values, is not interested in the question of whether the country should or shouldn't have a military, and doesn't care about whether being in the military is honorable. S/he would join the military of any country whatever provided it was advantageous enough to do so. I believe that there are many people who join the military whose reasons are like Person A's. But I think there's a pretty clear moral difference between the motives of A and B. Now of course there are also people who join the military...

My short answer is that we don't need to be able to visualize higher-dimensional spaces in order to reason about them. I'd be quite astonished if Stephen Hawking could visualize 11 or 26 or even 5 dimensions. In fact, visualizing even three dimensions is not as easy as people think, as one realizes when trying to think through certain "ordinary" geometrical descriptions. But there are tricks that can sometimes give you the sense of visualizing higher dimensions, as with various diagrams of a four-dimensional "hypercube." Here's an example: https://plus.google.com/117663015413546257905/posts/VteWm45DCff Turns out that what I've said is more or less what the well-known physicist Sean Carroll says here: http://www.preposterousuniverse.com/blog/2009/03/30/why-cant-we-visualize-more-than-three-dimensions/ though he adds some speculations that you can evaluate for yourself. But on the question you ask, it's (1) you can't, (2) you don't need to, and (3) there are all the same some tricks.

I'm going to step through this carefully to make sure I follow. We have two theories: A and B . Theory A has an assumption: A and theory B has an assumption B . And A and B are mutually exclusive—can't both be true. Let's pause. To say that a theory has an assumption means that if the theory is true, then the assumption is true. It doesn't mean that if the assumption is true, then the theory is true. A silly example: the special theory of relativity assumes that objects can move in space. But from the assumption that objects can move in space, the special theory of relativity doesn't follow; you need a lot more than that. Otherwise, the "assumption" would be the real theory. You ask if it's true that neither theory can prove anything about the other. If I understand the question aright, it's not true. For one thing, trivially, if we take A as a premise, then by your own description, it follows that B is false. That seems like a case of proving something about B ...

It's perfectly reasonable to ask moral questions about killing animals. It's not a trivial issue. But it's also perfectly reasonable to ask whether all animals are morally equal. You say that in the eyes of God, all being are equal. But even taking it as given that there's a God, I don't see much reason to believe that. And in any case, trying to sort out what God might think about things is a slippery route to moral conclusions. What matters isn't what God's conclusions might be; what matters are the reasons. In many cultures, it's common to eat insects—ants, for example. Do we really think that killing an ant and killing a human being are morally on the same level? It's not obvious that they are. Ants are alive; there's no doubt of that. But so are bacteria. So are lettuce plants. We don't think that it's wrong to kill something simply because it's alive, and so among living things there must be distinctions—features of the living beings that make it more or less wrong, or even not wrong at all...