Killjoy

I am new to this discussion board so I hope people will forgive me if I cover ground that has already been done to death. The usual story on the source of moral values is that they come either from social convention or from God. The problem with the former is that it leaves no room for the possibility that society itself is morally corrupt. The problems with the latter are too numerous to mention here, and I'm sure have been amply discussed elsewhere.

I think it is possible to give a definition of morality which is more or less universal. Here is my attempt.
First define a "moral agent", very loosely, as any being that is sentient, conscious, whatever similar word you like - essentially anything that is able to want, capable of having genuine desires, etc. There will, of course, be controversy as to what counts as a moral agent. Humans certainly do; higher animals probably do; intelligent life on other planets probably does; insects probably don't; bricks certainly don't; etc.
Next define a "morally neutral act" as any activity carried out by a moral agent that does not in any way affect any other moral agent.
I can now define a "moral act" as any act that assists a moral agent in performing a "morally neutral act" or a "moral act", OR inhibits a moral agent from performing an "immoral act". Similarly I define an "immoral act" as any act that assist a moral agent to perform an "immoral act" OR inhibits a moral agent from performing a "moral act" or a "morally neutral act".
Note that while this definition appears circular it is actually "recursive", a valid concept borrowed from computer science and linguistics and used extensively in these fields. Perhaps a simple example will clarify it.
Suppose I am walking down the street minding my own business. This is a morally neutral activity. Person A approaches and attempts to detain me - perhaps by tying me to a tree. This is an immoral act. Person B comes to my assistance by trying to thwart the activity of person A. This is a moral act. Person C tries to prevent person B from assisting me. This is an immoral act. Etc.

The primary idea behind this definition is that, by simple symmetry, the wants and desires of any moral agent should be equivalent - all other things being equal. This is as opposed to other definitions which have the primary source of morals as evolutionary expedience, social conventions or the dictates of religion. As already mentioned these all suffer from the same problem - it is always possible to give examples where they do not match our intuitions about what constitutes moral behaviour. While I am fully aware that simply announcing a new definition of an old concept will not make that definition acceptable, I believe the definition above is a closer match to our intuition on morality than any of the others.

I am also aware that it will not, of itself, answer all burning moral issues in society. There will always be doubts as to what constitutes a moral agent, what moral agents actually want, what acts are really morally neutral, etc. However, applying this definition has already helped me decide my own position on issues such as euthanasia and embryonic stem cell research.