## Hello there,

Hello there, I have a question about why exactly there's a problem or a paradox with the concept of Bleen and Grue from N. Goodman's writings on the New Riddle of Induction. I understand that at time T, the color is Bleen (or Grue) and that any prediction we make about a color of some object (for example) can be green or blue- and it will be right. Is that the essence of the paradox? Can I claim that it is similar to Schrodinger's cat paradox? If we examine an object after time T, and it's green then its original color should be named Bleen, but I have hard time understanding why it is so?

The paradox concerns the logic by which we are justified in forming our expectations about the future. Suppose we observe a bunch of emeralds and at the time that we observe them, each is green. This evidence is generally thought to support our expectation that on the first occasion on which we observe an emerald after the year 2100, let's say, we will find it to be green. The pattern of reasoning seems to be "If every F [emerald] we have examined has been found to be G at the time we observed it, then we should expect any given F to be G at any future time at which we might observe it." However, this pattern of reasoning (Goodman shows) cannot in fact support our prediction. For suppose that instead of making G = green, we make G = grue, where an object at a given moment is "grue" at that moment if and only if that object is green at that moment and the moment is (let's say) before the year 2100, or the object is blue at that moment and the moment is during or after the year 2100. So every emerald we have examined we have found to have been grue at the moment at which we examined it (since it was green at that moment, and the moment predated 2100). Therefore, by the principle of reasoning I gave above, we would be justified in predicting that the first emerald to be examined after 2100 will be found then to be grue -- that is to say, blue. But we do not regard the greenness (i.e., grueness) of the emeralds we have checked to support the prediction that some emerald after 2100 will be blue (i.e., grue). Therefore, the above principle cannot be the basis of our prediction regarding emeralds.

I see no connection here with the Schrodinger's cat paradox, which concerns the entanglement in quantum mechanics between macroscopic objects (such as a cat) and microparticles (such as a radioactive atom).

With regard to the final paragraph of your question: If we examine an object after T (2100, in my example) and it is green at that time, then the object at that time was also bleen (i.e., blue at that time, if the time was before 2100, or green at that time, if the time was at or after 2100). But for an object to be bleen at a given time (say, after 2100), it does not always have to be bleen. An object that is always green, both before and after 2100, was grue before the year 2100 and bleen after the year 2100. For an object to be bleen at a given moment, it does not have to change color at the year 2100; if the moment is before 2100, then the object is bleen at that moment as long as it is blue at that moment, no matter what it may do after 2100. If it remains blue, then it was bleen before 2100 and later is grue -- just as for an object to be green at a given moment, it does not have to remain green later.

I should caution that Goodman's problem can be posed in terms of various different definitions of "grue" and "bleen". I have used here the definitions that I think pose the problem most easily, but others (including Goodman himself) define "grue" differently for these purposes.

## Is it plausible the theory of "occam's razor". Could a complex answer be the

Is it plausible the theory of "occam's razor". Could a complex answer be the right one?

You ask an important question. Some philosophers (realists) argue that simpler theories are better confirmed by the data and therefore more likely to be true. Other philosophers (anti-realists) argue that simpler theories are psychologically easier to work with and therefore more convenient for us, but not likelier to be true.

It is difficult to state exactly what counts as a "simple" scientific theory. Does it mean fewer causes and/or entities? Or something about the mathematical expression of theory? In any case, simpler theories are only preferred when all else is equal, and that is rarely the case. (We would love a simple theory of the causation of schizophrenia, but simple theories of the etiology of the disease have already been discredited.)

Some feminist epistemologists have argued that simple scientific theories are not inherently preferable to more complex ones. Helen Longino, notably, argues that simple scientific theories often reflect/express/derive from a hierachical ideology of single powerful causes, and that more complex theories (often reflecting a more egalitarian ideology of interactive causes) should be proposed and taken seriously more often.

## I am often confused by the rhetorics of physicists that their theory "came from

I am often confused by the rhetorics of physicists that their theory "came from mathematics". I remember the physicist, Brian greence tell the story of paul dirac discovery of anti-matter by pure a priori manipulation of mathematics. I see this to be very confusing, because i often imagine mathematics as being a priori, and necessary without any connection to the real world. That is, i can always imagine possible worlds( or universes) governed by different mathematical expressions, or descriptions. Does it follow that every mathematical expression/description describes our universe? Obviously not. With paper, and pencil, we could probable describe any universe with any arbitrary number of dimension of space, but does it follow that our universe has arbitrary number of spatial dimension? Obviously not. The use of mathematics seems to be good in formulating regularities of nature( laws of nature), and to extract the implication of those laws. It makes me wonder why physicists would say their theory comes...

You are reasoning correctly--mathematics deals with possibilities and physics with actualities (even though in quantum mechanics these are probabilistic). Theory in physics is often expressed mathematically, but that does not make it mathematical knowledge. Some theoretical advances in physics can come from working in an armchair and extending the mathematical implications of (already accepted and contingently true) theory. The actual status of mathematics (a priori or not) is debatable (Quine etc claiming that mathematics is an empirical theory like any other). But you are correct that physics is not mathematics, and the sort of evidence that confirms physical theory is not (or perhaps, not entirely) the evidence (or other considerations) needed to confirm mathematics.

## Are all of the laws of nature or of the universe such as the law of gravity

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 the relevant point for our purposes is just that this is a different issue than whether the law has exceptions.

## I read recently a comment by a philosopher that Karl Popper's "falsifiability"

I read recently a comment by a philosopher that Karl Popper's "falsifiability" theory is considered obsolete. Is this so? I always found it to be quite useful. If it's obsolete, what rendered it so, and by what was it replaced?

I'll add a third problem to Popper's views... it classifies obvious psuedo-sciences as sciences such as astrology, so long as they make potentially falsifiable predictions. Furthermore, it does nothing to distinguish something radically implausible like astrology from something more plausible, but not falsifiable such as ad-hoc psychological analysis. Popper's views and others similar to it (verificationism and logical positivism) belong to an era of philosophy when it was believed philosophy could be made 'scientific'. It has not really been replaced because few philosophers still hold to that belief.

## Occam's razor seems to be a devestating weapon when it comes to the atheist's

Occam's razor seems to be a devestating weapon when it comes to the atheist's argument to why God doesn't exist, or more precisely it is more likely that he doesn't exist. It seems the scientific community has the consensus that they will never rely on "God" for the answer to any problem. Will there ever be a scenario in which God might prove simpler than the scientific or mathmatical explanation, and Occam's razor can be used to justify a belief in God?

What if a burning bush appeared out of nowhere in Central Park in front of hundreds of people and said, "It is God speaking. I have come to tell you that you should believe that I exist. Also, love one another. And, by the way, the health care bill does not say anything about a 'death panel'"? Well, a scientifically minded person would want to consider various alternative explanations for this event. For instance, perhaps it's an elaborate hoax involving holograms or even mass hypnosis. But another hypothesis worth considering is that it was God, and God is able to perform miracles that cannot be explained by anything the sciences study (or could study). There might be ways to test whether this event was a hoax, but presumably a 'hoaxster' would try to cover his tracks.

So, what if an agnostic scientist in the crowd said to the burning bush, "I would like to believe in God but I need evidence that the best explanation for this event is that you really exist and that this isn't just a hoax. Please plan to appear again in a laboratory I will secure at noon tomorrow (of course, you'll know where to go, right?)." She then secures a lab that cannot be 'hoaxed' and sets up various equipment to measure everything she can, such as whether matter or energy is coming into the lab from outside, etc. God appears at noon and has a long conversation with the scientist and dozens of witnesses of various beliefs and backgrounds (brought in at the last minute so they couldn't set up a hoax). God explains some mysteries, maybe even explains how it is the he exists outside of physical space-time yet can interact with it, etc.

Well, now I think the best explanation for these events is that God exists (i.e., the entity that calls himself God and has these powers and this knowledge exists) and that God caused these events. It looks like applying Occam's razor here would suggest this explanation is superior to any scientific or mathematical explanation (at least any that we could currently offer, without ad hoc adjustments). It may be that we could eventually develop scientific explanations that would account for this God, but they'd be very different, it seems, than our current paradigm.

Meanwhile, as far as I can tell, none of the actual events (or interpretations of them) that people have thought are better explained by the existence of God than by potential scientific explanations are actually best explained by the existence of God. I could, of course, be mistaken.

This suggests to me that if God exists, God does not want it to be easy to believe in him based on our best evidential standards. Perhaps this is where faith is supposed to come in.

## According to Karl Popper, a hypothesis is scientific if it can be

According to Karl Popper, a hypothesis is scientific if it can be observationally falsified, not, if it can be verified. One instance not in accordance with a supposed law refutes the law, but many instances in conformity with the law still do not prove it. Accepting this falsification test, we may remark that the idea of the divine existence either could, or could not, be falsified by a conceivable way of observation. If it could not, then science in no position to test theism. Please comment. Thanks

I'm not as confident as Peter Fosl about the testability issue: perhaps we need to know a bit more about what counts as "the theistic hypothesis".

After all, a lot of theistic hypotheses look perfectly testable by ordinary scientific standards. Take, for example, the claim that Zeus exists. I take it that no one now reading this site believes that that claim is literally true! But why? Well the existence claim, taken literally, is bound up with a range of stories about how the world works; and we now know the world just doesn't work that way. Mount Olympus is not populated with gods; bolts of lightning are naturally caused discharges of electricity; clouds and rain are not gathered by supernatural agency; burnt sacrifices to Zeus do not increase the chances of better crops or victory in battle; and so it goes. Science -- in the broadest sense of our empirically disciplined enquiries into how things work -- has shown we have no need of the Olympian gods to explain anything. Of course, that doesn't mean that the Greek myths aren't full of insights into the secrets of the human heart! But in so far as they essentially embody creation stories and stories about the origin of natural phenomena like storms and tempests, science -- in the broad sense -- uncontroversially shows that they are literally false.

So if someone claims that the empirical testing methods characteristic of science can't in general impact on the questions about the existence of various gods, then that's surely wrong. Which raises a nice question: why should the question of the existence of the Judeo-Christian God (the theistic hypothesis, perhaps) be different in this respect from the question of the existence of Zeus?

Well, the questions won't have a different status if we take the God-story also to be essentially bound up with e.g. certain biblical creation stories. Science has more than adequately shown that those stories aren't literally true. And again, petitionary prayer to God is no more effective in bringing about worldly goods than sacrifice to Zeus (it does no better in helping you recover from illness, say, than can be explained as a placebo effect). In so far as claims about the existence of God are bound up with specific such claims about how the world works, science can impact. And indeed, does impact strongly negatively.

But of course, sophisticated, scientifically knowledgeable, believers can and do react to that point in (at least) two different ways. One way is to try to keep a theistic hypothesis as a true factual claim, but aim to protect it by disentangling it from creation myths, and other such stories about how the world works: though you might well begin to wonder, as God becomes more and more abstract, more remote from the quotidian world in which we live our lives, why we should care. Another way (characteristic I think of one strand of English Anglicanism) is to agree that in so far as talk of God is bound up with stories about how the world works, it is encroaching on the province of science and is (mostly) literally false. However, you then go on to emphasize that this doesn't mean that the Christian myths, say, aren't very good myths to live ones life by, or that sharing Christian ritual practice isn't a sustaining prop to living a good life in a community.

## I'm a scientist. The results of my research may generate technologies that could

I'm a scientist. The results of my research may generate technologies that could potentially be used in both and offensive and defensive military applications. These same technologies could potentially help people as well. Here are two examples: (1) My work could potentially create odor-sensing devices to target "enemies" and blow them up, but the same work could aid land-mine detection and removal. (2) My work could help build warrior robots, but it could also help build better prosthetics for amputees. For any given project, I have to decide which agency(ies) my lab will take money from. I do not want to decide based on the name of the agency alone: DARPA has funded projects that helped amputees and killed no one, while I would bet (but do not know for sure) that some work sponsored by the NSF has ultimately been used in military operations. So I'd like to base my decision on something more than the agency acronym. How can I start to get my head around this? What sorts of questions should I...

I am happy to read Miriam's and Thomas's replies to this question, because it is one that I somewhat unexpectedly faced when I switched from being a professional philosopher to being a professional computer scientist (albeit one with a highly philosophical bent!).

The first time the issue came to light was when I gave a talk to computer and cognitive scientists at the University of Texas at Austin about 20 years ago. One of my hosts was Benjamin Kuipers, a leading researcher in artificial intelligence, who had done groundbreaking work, as a grad student supported by military funding, on "way finding": How to program computers to give and to follow geographic directions. He told me that after he got his Ph.D., he realized that, as a practicing Quaker, he could not in good conscience continue to take military funding, especially if that meant that he would have to fire grad students or postdocs who would be working under his direction if the military asked him to do something against his beliefs and thereby took away his funding. So he changed the entire line of his research to medical applications of AI, which were funded by such organizations as NIH. His full story and arguments in favor of not taking military funding can be found on his website in an article titled "Why Don't I Take Military Funding?" .

The second time the issue came to my attention was when a visitor to our computer science department at the University at Buffalo lectured about autonomous vehicles--automobiles, equipped with AI-programmed computers, that can drive themselves--a project funded by DARPA. During the question session after the presentation, one of my colleagues, Tony Ralston, asked this question: "How can you justify this research when obviously its main purpose is to develop autonomous military vehicles for warfare?" Of great interest to me was that during the reception afterwards, the conversation focused around two groups: students and faculty asking the visitor technical questions, and students and faculty asking Tony Ralston questions about the ethics of militarily-funded research. Another colleague, also a practicing Quaker, suggested that it was OK to take such funding on the grounds that the work she would do was not aimed at killing people--better that the military give their money to her than to someone with other ideas.

My personal decision has been to refuse military support. There have been some negative consequences (lack of funding, etc.), but I feel comfortable with my decision.

But read Kuipers's arguments--they're quite interesting.

## Does one have to know from the inside through experience the kinds of things

Does one have to know from the inside through experience the kinds of things social scientists study such as religious practices, chivalry, the earlier ways of life of native Americans, and so on, if one is not to distort such things or even just propagandize for or against them? Danke im voraus!

The ability (and perhaps inclination) to distort or propagandize is deeply human, and I see no reason to think that one is less likely to engage in such things from an "insider's" perspective than if one takes (or cannot help but be in) an "outsider's" position. Indeed, in some ways, I would expect these tendencies to be greater from "inside" than from "outside" perspectives, since those of the former group do, whereas the latter need not, have anything personal at stake. If I follow a certain religion, or have been raised to accept and engage in a certain cultural practice, or am a member of a certain ethnic group, it is natural for me to want to defend that religion, practice, or group--and to minimize or ignore the way(s) in which my religion, practice, or group may (even rightly) be seen as mistaken or wrong. Obviously, one's access to all the pertinent evidence for sound judgment may be more difficult, the further "outside" one is from the sources of such evidence, but at least one can be free of the biases inherent to one's sense of belonging to a religion, culture, or ethnic group.

## For months I have had an exhaustive debate with various colleagues on the ethics

For months I have had an exhaustive debate with various colleagues on the ethics of testing for correlations between race and IQ. I have arrived at the conclusion that while current methodological quagmires surrounding the testing render the results of such a study untrustworthy at best and potentially racist at worst, I still think that in the interests of free inquiry such tests proceed. However, the question remains, can a study on intrinsic group differences which is fraught with methodological uncertainty and whose results have relatively narrow applicability have any ethical basis? Are there other considerations for deciding whether such a study should or shouldn't be conducted?

I am no expert on these matters. (For an expert opinion, you might consult Philip Kitcher's recent work.) But I would like to point out that "the interests of free inquiry" is an ambiguous phrase. It is one thing to say that ethically, such a study should not be conducted. It is quite another thing to say that the government or some collection of private citizens should take action to prevent a scientist from conducting such a study. Just as "free speech" considerations prohibit the government from preventing certain kinds of speech but do not deem all speech to be ethically permissible, so "the interests of free inquiry" may prohibit the government from preventing certain kinds of studies but do not deem all studies to be ethically permissible.

An interesting question is whether a private grantmaking organization should fail to fund such a study. Considerations of "free inquiry" do not require it to be blind to the reasons why such a study might be unethical (just as the interests of "free speech" do not require that a private university or other private institution provide a forum for advocates of all sides in a dispute to speak). When the government is the grantmaking organization, matters get even more complicated.

So what I am trying to say is that there are several questions here: (i) is such a study ethical? (ii) If not, how should that fact be taken into account by governments, grantmaking organizations, scientific institutions (such as journals and universities), and individual scientists themselves (where the answer may be different for different members of this list)?

As for whether such a study is ethical, I would say (speaking nonprofessionally -- I am not an ethicist) that if it is reasonably believed that the outcome of such a study would likely be grossly misused by the public at large, then that fact constitutes a strong (though perhaps not decisive) reason to believe that it would be unethical to conduct such a study. (Other reasons would have to be weighed against this one, including whether any benefits might result from carrying out such a study.)