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...

Adding to Professor Solomon's good points: One question that you seem not to be raising, but should, is whether research is alright when it does more good than harm. This cannot be universally correct. Think of the Tuskegee experiments. Or think of the horrific experiments German and Japanese doctors conducted on prisoners. The latter experiements apparently yielded very useful results -- so useful that the US offered immunity to doctors willing to share their knowledge and know-how. Still, participation in such experiments is generally wrong even if, in the long run, the benefits outweigh the harms. Philosophers have discussed these issues -- often in the context of criticizing or defending utilitarianism (or, more broadly, consequentialism) -- under two headings (which will enable you to retrieve relevant literature). They have debated whether negative duties (not to harm) have greater weight than positive duties (to help or benefit). And they have debated whether harms that are intended ...

I would appreciate some recommendations on texts (for a layperson -- a nonprofessional philosopher) whose subject is the philosophy of science.

Perhaps start with a look at the entry "scientific explanation" in the Stanford Encyclopedia of Philosophy ( plato.stanford.edu/entries/scientific-explanation ). After that, I would get started with three classics: Sir Karl Popper: The Logic of Scientific Discovery (1959) Ernest Nagel: The Structure of Science: Problems in the Logic of Scientific Explanation (1961) Thomas Kuhn: The Structure of Scientific Revolutions (1970).

Can there ever be a meaningful distinction in science between the "unknown" and the "unknowable"? I see no reason why science should not,in 100,000 years or so, unlock what now seem to be unknowable questions like the nature of a Prime Mover, if he exists, simply by accruing more and more knowledge of the universe. We know pretty much what happened a trillionth of a second after the Big Bang and we acquired this knowledge in about 100 years so why assume everything before that is unknowable? Surely the scientific method would insist that this is "presently unknown". Is it that metaphysics and the persistence of religious belief color our approach? Is "unknowable" even a valid term in philosophy, and, if so, what definitive, unassailable examples are there of it (which would also apply, say, 100,000 years from now)? Thanks in advance.

Let's begin by distinguishing two senses in which something might be said to be unknowable. In some cases something is said to be unknowable because it isn't the kind of thing about which, in principle, knowledge could be had. For example, do you know the minimum number of hairs a man must have on his head to escape being bald? Well, there is no such minimum number to be known or discovered, because the concept of baldness is too vague for this. Do you know what time of day it is now on the sun (Wittgenstein)? Would you be happier dead? Again, there's nothing to be known or discovered in these regards. Philosophers have said about such cases that "there is no fact of the matter." Let us set these cases aside, because they are not the ones that interest you. In the cases that interest you, there is a fact of the matter. And the claim is then either that it is impossible for us (human beings including all future generations) to know this fact or even, more dramatically, that it is in principle...

The debate between science and religion has gone on for many years, and many people think that they must choose one or the other to believe. To me, it's a lot like trying to collide two trains on parallel tracks. If one chooses to believe in God, then that person can still believe in the big bang or evolution while believing that God created the universe, because religion explains what happens on a spiritual level, and science explains what happens on a physical level. The two run parallel. Using this as a way of thinking, can science contradict religion at all, and why has the debate between the two gone on for so long when this explanation reconciles them?

Your idea works fine on a certain modest understanding of religion. If religion were only about the Divine, perhaps with the additional thought that God created the universe, then no explanation given by science of anything in the universe could interfere with religion. Religions are typically not so modest, however. A typical religion may ascribe certain duties to human beings along with the freedom and responsibility to live up to these duties. And this can raise scientific (and philosophical!) doubts about whether human beings have the requisite freedom. In response, you might propose dividing human beings over your two levels: into a physical body (brain included) and a spirit or soul. But this proposal raises further puzzles about the relation between these two parts or components of human beings. If religion attributes some of what you do to your soul it may compete with scientific theories that attribute all your conduct and thinking to physical causes. If religion attributes nothing you...