I suspect this will be exactly the type of complicated answer you have in mind, but... philosophers often do succeed in giving concise answers to important philosophical questions. Here are two almost randomly-chosen one liners: Difficult question #1: What makes an action morally right or wrong? Consequentialist answer: An action is morally right if and only if it maximally satisfies the interests of all those affected. Difficult question#2: How can we freely choose our actions if they are brought about by micro-physical processes (be these deterministic or indeterministic)? Compatibilist answer (roughly): Our actions are free if and only if they follow in the right way from characters of the right type. These are succinct answers, and in that sense "simple. But the devil is in the details, of course. The complications come in when we specify how we should understand the answers' central formulations--for example, what counts as an 'interest"?; what is "following in the right...

Cultural relativism, as it's restricted to moral matters, might be described as the view that what's right and wrong is relative to culture--the moral status of a given action or practice depends upon the moral code of the culture in which that action is performed. There are lots of variations, but I think that get's the general idea. Cultural relativism is meant to capture the idea that polygamy, for example, is not absolutely right or wrong: it might be wrong in one culture but perfectly acceptable in another, and neither culture is morally superior to the other. My own view is that cultural relativism is neither good nor bad, but wildly implausible. Here are a few reasons: First, and most imortantly, I don't think that on reflection we really believe cultural relativism. We confuse it for attitudes like humility and tolerance that we do believe in. There are lots of practices--human sacrifice, infanticide, extreme torture, sanctioned rape--that may be morally acceptable in some cultures,...

I suppose it depends upon how you understand these effects. Take "motion trails". If we regard these as illusions--that is, we hold that there aren't really colored trails that follow a moving object like colored silk scarves attached to the end of the object--then the drug may be allowing us to have certain illusory experiences that we might not otherwise achieve, but it isn't allowing us to see colored trails that actually follow objects, since there are none. So LSD allows us to have an experience as of a motion trail, but not to actually see one in the world. (This is just what we should say about the straight pencil that looks crooked in a glass of water: I have a visual experience as of a crooked pencil, but am not actually seeing one, since there is none to be seen.) This is not to deny, though, that drugs may heighten our veridical perception of our environment. That to me is the most interesting feature of drugs. Perhaps LSD does this at times, but I wouldn't know.

This is a natural and important question to wonder about. It is also an old and distinguished one, dating back at least to John Locke. In its modern incarnation it's often called the problem of "spectrum inversion" or "qualia inversion". Two people might make all the same color discriminations, and use color language in all the same ways, so that outwardly (from a third-person perspective) we would have no reason to say that colors don't "look the same way" to them. But how can we be sure? Isn't it possible that a red object looks to me exactly the same way a green object looks to my functional twin, and vice versa? There is currently a raging disagreement about this, and it leads directly into the fascinating and vexing mind-body problem. Much of the debate turns on what we should mean by "the way a color looks" or "the qualitative character" color experience. Some hold that the way things look or seem first-personally does not go beyond the way that a person reacts to, processes, and acts upon her...

I also find that saying suspicious, though I'm not sure I accept your suggested argument against it (more on that in a moment). I disagree with the saying because there seem lots of clearly impossible states of afffairs: that 2 and 2 could equal 5; that I could both win and not win the tennis match (in a fixed sense of "win"), and, pehaps more controversially, that I could have had different biological parents than I did. (For more on the different senses of "possible" see Alex George's answer to question 71: Is nothing impossible?) In fact, though, I particularly dislike the saying when people use it to generate false optimism. It is not, alas, possible (in the relevant sense) for me to win the olympic marathon, to be an international multi-billionaire, or to be a wildly successful tabloid heart-throb (well, maybe there's still time for that...). And no snake-oil or course of instruction on the internet will change this, even if the packaging proclaims that everything is possible. Now to your argument...

It might be worth adding, nevertheless, that there are some facts that obtain in virtue of enough of the right people believing that they do. You and I are "going out" if and only if we each believe that we are--or so it seems. It also seems that the market will go up if and only if enough of the right people believe that it will. As Alex rightly points out, though, these cases cases don't extend very far--e.g., to making the sun rotate about the earth.

There are systems of conduct that individuals or their societies aspire to live by, and then there is the philosophical study of these--that is, the attempt to answer questions such as whether there is really a universal right or wrong, whether (and if so, how) moral claims are grounded in facts, and so on. 'Morality' sometimes refers to the former, and 'ethics' to the latter; but this isn't standard, as far as I know. Sometimes 'ethics' is used to refer to the former, as in "I question his ethics".

More space: someone more versed in astronomy can correct me if I'm wrong, but I believe "outer space" just refers to spatially-extended bits of the universe beyond our galaxy. I'm not sure I agree, though, that everything has to take up space. What about numbers or colors or God(s)...?

The society of poker players displays a kind of procedural fairness--if everyone starts with the same amount then there is no one to blame for future discrepancies other than Lady Luck and the players' own decisions. But is this type of procedural fairness all that is required in a just society? Many would argue that a just society, or more broadly a good society is one that takes care of those below a certain level of well-being no matter how they got there . In many cases it's just bad luck when a person's life is turned upside-down by natural disaster, but I don't think we would consider a society good if it therefore did absolutely nothing about this suffering.

This is difficult to answer briefly. And there are certainly books and courses that will give you a comprehensive and useful answer. As a start, though, critical thinking involves scrutinizing and evaluating the reasons given (in a newspaper, on TV, in conversation, etc.) for believing some claim or piece of information. Broadly speaking, these reasons come in two flavors. First, certain claims are said to follow from others "logically": the given claim has to be true given the other claims that have already been accepted. (The butler did it because all the other suspects have now been ruled out.) Second, the claim is true because it is grounded somehow, often statistically, in empirical data like observations. (Polls suggest that the president's popularity went down because of the response to Hurrican Katrina.) In practice, these two types of reason--deductive and non-deductive--are often mixed together and difficult entirely to separate. It's useful, though, to separate them in the study of...