What do people mean when they say (as when cautioning against the validity of a scientific study, for example) that "correlation does not imply causation"? Isn't causation just perfect correlation? And if so, doesn't that mean that the caveat in question does not concern causal claims per se, but inductive claims more generally?

Suppose there is a single type of event A that always causes two other events, B and C. Suppose, moreover, that, whenever B occurs, it is always caused by A, and similarly for C. Then B will be perfectly correlated with C, but by hypothesis is not caused by it. This is typically what people worry about, though of course the correlation is rarely perfect, in fact. For example, people with AIDS almost always have HIV. There's a very strong correlation. We also know now that HIV does cause AIDS. But the correlation by itself does not show that HIV causes AIDS. Maybe having HIV is actually another effect of whatever it is that actually causes AIDS. Your immune system is depressed, and so you have this virus that other people do not have. Not actually true, but it might have been true. But perhaps what is bothering you is a slightly different thought: This kind of strict correlation can't just be accidental, can it? Surely something must explain it! But, as I have said,...

Video games cause violent behavior. Is that an example of a baseless speculation or is it a reasonable but vaguely founded idea? It seems somewhat plausible but its plausibility seems kind of vague so I can kind of sympathize with the ultra-logical "Reason Magazine" types dismissing it out of hand. On the other hand that kind of dismissal which says that if you can't think of a definite reason for an opinion then it's wrong seems kind of glib, because their does seem to be something to it. After all as general psychological rule we tend to think that encouraging a behavior leads to a behavior and some people might see imaginary violence as a form of encouragement.... but it really does seem like a kind of reasoning that lies somewhere between gut instinct and reason doesn't it? I guess my question is really more epistemological than directly pertaining to the question of whether or not images cause violence. Is this simply a case of balancing human social instinct over pure reasoning or is there a more...

The question whether video games cause violent behavior is an empirical one. That is, it's one that has to be decided by looking carefully at the evidence, not by reflection on what seems plausible and what doesn't, and anyone who would "dismiss" such a claim "out of hand" is not being very reasonable at all. Nor is someone who bases such an opinion on a vague feeling that "imaginary violence [is] a form of encouragement" being very reasonable. Fortunately, the social scientists who study these sorts of things have other tools. That is not to say, of course, that the tools are sufficient to answer the question, and of course it continues to be controversial whether video games, or other sorts of "media violence", lead to increased violence in practice. It's difficult to account, in practice, for all the variables. That said, I think most researchers would agree that exposure to media violence does tend to make one less sensitive to the real suffering such violence causes and so does tend to make one...

When proponents of Intelligent Design insist that it is inconceivable for a particular biological structure to have simply evolved, their opponents sometimes respond "evolution is cleverer than you are." This is a pithy response, and no doubt there is truth to it; but can the ID-proponent really be reasonably expected to accept this?

Whether ID proponents would accept the counter is not necessarily the best question. I would suggest we ask whether they should accept it, or what force it has. My own sense is that the charge that it is "inconceivable" how, say, the eye evolved is really quite lame. Suppose it true that it is utterly beyond the imagination of human beings how the eye might have evolved. So what? Surely there are plenty of things that are utterly beyond our imagining. That we can't figure it out in any detail, or even begin to do so, just doesn't show anything. One might ask why we should believe that the eye evolved, then. The answer, presumably, is that we have good evidence for evolution in general, that we can actually see it in action in simpler cases, and that one can tell some rough story about why and how primitive light-detection might have evolved, and even see a range of such sensory organs in actual organisms. Having any reasonable sense of how the eye, as it is, evolved over the eons isn't really...

Why can’t science tell us what morality ‘is’? In the trivial sense, science can certainly catalog the diversity, commonalities, and contradictions of cultural moral standards and moral behaviors. But science is very good at teasing out underlying principles. What forbids determining such principles (if any exist) using the normal methods of science? For instance, we might propose an observation like “Almost all moral behaviors are strategies for increasing, on average, the synergistic benefits of cooperation and are unselfish at least in the short term” as an hypothesis about what moral behaviors ‘are’. Then we could evaluate its provisional ‘truth’ as a matter of science by how well this hypothesis meets criteria for 1) explanatory power for the diversity, commonalities, and contradictions of moral standards, 2) explanatory power for puzzles about moral behavior, 3) predictive power for moral intuitions, 4) universality, 5) no contradictions with known facts, and so forth. Of course, provisional ...

I think science can probably tell us lots of things about how people reason morally, that is, how they think about what they ought to do. And it might well be interesting to look at cross-cultural differences, and perhaps even more interesting to look for cross-cultural similarities, that is, "moral universals", in the sense of moral principles, or forms of reasoning, that are in some sense universal. Psychologists and philosophers have been doing just this in recent years. But it seems important to recognize the contrast you cite at the end of your question: No such investigation could possibly tell us what moral behavior ought to be, that is, tell us what one actually ought to do. Suppose there turn out to be certain "moral universals". It would be a coherent position that these are just wrong, that is, that, by reasoning in accord with them, one will not typically arrive at the thing one ought to do. One cannot just assume otherwise. That is not to say that it would not be interesting, even on...

Are all of the laws of nature or of the universe such as the law of gravity necessary or contingent? If contingent, and found in one instance to be false, would they fail to be laws? Thanks, John

Yes, and no. If there are exceptions to the law of gravity (whatever that might be), then it is not a law. Fundamental physical laws are supposed to be exceptionless. (I put the point that way because many philosophers hold that the laws of non-basic sciences, such as biology or even chemistry, can have exceptions. But this is a different, and very tangled, issue.) However, the fact that the law of gravity (if it is really a law) cannot have exceptions does not imply that it is necessary. To say that the law is necessary is to say that it could not have been otherwise. Or, to use a popular metaphor, it's contingent if there is another "possible universe" in which the laws are, in fact, different, so that the law of gravity, as it is in this universe, does not hold there. The mere fact that the law holds without exception in this universe does not obviously imply that the laws might not have been otherwise. Some philosophers do think that the laws could not have been otherwise. But...

Could questions in the philosophy of language in principle be answered in terms of the structures of the human brain? Might we imagine, for instance, pointing at a certain lobe and saying "Well, this shows that Russell was wrong about denotation"?

Well, I don't know if it could be quite like that, but one dominant approach to contemporary linguistic theory holds that questions like, "How do descriptions work in natural language?" are ultimately questions about the psychology of competent speakers. Assuming that (cognitive) psychology in some sense or other ultimately reduces to facts about the brain, it follows that the question how descriptions work in natural language is, in some sense, a question about the brain. But the nature of the relation between psychology and brain-facts is the difficult question here.

What is relationship of philosophy (in particular, metaphysics) to physics? It seems to me that both disciplines, especially the "classical" metaphysics of the Ancient Greeks and the medieval Christians, attempt to understand the structure of reality, but physics focuses on the development of the material world of matter, metaphysics primarily aims at understanding the non-material world (including how it is related to and shapes the material world). Is this an adequate understanding? I would be very interested to hear your opinion(s) on this subject.

Metaphysics, as it was originally understood, was 'meta' to physics. That is, metaphysics was concerned with general questions about the nature of physics or, again, with foundational questions about physics. That's certainly the sense you get from Aristotle's Metaphysics , which I think is where the term originates, but also from Descartes and many of the other early modern philosophers. I don't know about the medieval Christians. But even they might fit this mold insofar as their loftier speculations are, ultimately, driven by concerns about the foundations of physical science.

i gleaned from a review of d. dennett's "darwin's dangerous idea" the notion that scientists' dogmatic insistence upon a purely materialist frame of reference may not be as justified as most students my age probably assume (also that scientists have brought this view to bear not simply in academia but in the political arena as well). the review included this outrageous quote from feyerabend: "scientists are not content with running their own playpens in accordance with what they regard as the rules of the scientific method, they want to universalize those rules, they want them to become part of society at large, and they use every means at their disposal -- argument, propaganda, pressure tactics, intimidation, lobbying -- to achieve their aims." all this is really kind of extraordinary to me! i really don't think that many studets my age were raised to question science on such a level (i'm pretty sure that if we did at this point, we'd be laughed out of the classroom as kooky i.d. proponents). i don't...

I'll just make a few comments about this. I don't have much detailed to say about it. First, I'm not sure that "scientists" do insist dogmatically upon a materialist frame of reference. A broadly materialist—or, better, naturalistic—orientation is hardly optional within the practice of science itself , but there are plenty of scientists whose conception of the world as a whole is a bit more expansive. I don't say this to congratulate or insult anyone, just to note it. That said, it is true that some people, some of them scientists, do sometimes try to push materialism beyond the bounds of scientific practice. The important thing to note is that, in doing so, they are pushing a bit of scientific methodology beyond its natural home. I take it that this is Feyerabend's point, one he makes in characteristically colorful language. But that point has been made by several others, too, sometimes in more local ways. I'd strongly recommend, for example, some of Noam Chomsky's writings on naturalism.

Is there any fundamental difference between an individual's beliefs (say, religious belief) and empirical knowledge (say, scientific knowledge)? The former is clearly based on faith: the individual believes that e.g. God exists because he believes what his religious texts, his parents, his teachers, his peers, the media he chooses to consume say. But is that not the same in the latter case? The individual believes that Earth is round as opposed to flat, not because he has actually seen Earth from above or performed any other relevant experiments, but simply because he believes the textbooks, his parents, his teachers, his peers, and the media. The average individual's "knowledge" that the Earth is round is based entirely on hearsay. The same holds true for many other "facts" (even non-empirical, a priori ones). In this light, isn't our level of assuredness in these facts rather irrational and quasi-religious?

There are a couple different issues here that need to be disentangled. One concerns what philosophers call "testimony". It's clear that one way of knowing something is being told: If you can't know that the earth is round because you were told, then, as you note, very few people know that the earth is round. Now, as always in philosophy, there is much disagreement about how why one can come to know something by being told. But most people would agree that testimony is only a means by which knowledge may be transmitted : If you tell me that p , and I now know that p , you must already have known that p . Maybe you were told that p by someone else. But the chain has to bottom out somewhere, with someone who knows that p "of h'er own knowledge", as a lawyer might say, that is, not because s'he was told. Testimony therefore seems a distraction here. The problem of religious knowledge concerns how one might know (say) that God exists otherwise than by being told. If...

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