I would definitely agree that I have only very limited experience with logical reasoning in any kind of a formal setting (great web site by the way. I'll start going through it more thoroughly pretty soon). However, your example of a classic logical argument (major premise, minor premise, conclusion) doesn't quite hit the mark. That particular argument is valid from the logical standpoint, and it's validity from a "truth" standpoint depends entirely upon the accuracy of the two premises.
However, it appears to me that premises 1 and 3 in your argument will
only be accepted "as is" by someone who already agrees with your conclusion. This means that those premises will only be
made by someone who already accepts subjective morality to be the truth. I suppose that this might mean that the argument isn't circular from the technical standpoint, but I still think that your argument is kind of weak. Let's go back and take a look at your syllogism again, because after another look, it appears that your third premise is the weakest.
1.
Morality is based on desires.
Okay, the initial premise makes a broad, sweeping statement, which is always very difficult to back up. The gist of this premise is that any kind of moral decision is based on the desires of the person making the decision. This is (as you said) debatable, but I'm not going to try to debate it at the moment.
Now before moving on to the second premise, I feel obligated to take a slight detour to point out something a little off topic. The statement that morality is based on desires is a moral statement, at least, it appears that way to me. (This would imply that you simply
want morality to be based on desires?)
2.
If morality is absolute, desires are absolute
Okay, this is a simple, valid logical deduction, whose accuracy is entirely dependent on the accuracy of the initial premise.
3.
Desires are not absolute
This statement has an assumption that I never really thought about in much detail until recently. For this statement to be true, God cannot exist, but this is an unproven assumption. So your third premise rests on the unspoken, unproven assumption that there is no God. The other possibilty (that I see) is that it only refers to humans in general, because of the difficult nature of debating supernatural entities. However, this possibility can only be used if the entire syllogism was intended to refer to human ideas of morality in the first place. This doesn't appear to be the case, but if it had, this would require yet another unspoken, unproven assumption. This time, the assumption would be that man is the only (or highest) source of morality.
socrastein said:
OUR moral statements are based on what we desire, and OUR desires are not absolute. Therefore morality is subjective. Like I said a long time ago in this discussion, even if there are transcendent metaphysical morals, we can't access them, we can't know them, we can only know our own desires and our own morality. Absolute morality has nothing to do with humans, and whether or not it exists does not change the fact that morality is subjective for us humans.
It is true that
our moral statements are based on what we desire (barring those who have made someone else's desires, like God's, their source of moral decisions). However, when you go on to state that morality is subjective, you are assuming that man is the source of morality. This is probably the crux of the debate, and so clearly there has to be some kind of argument for it.
You do go on immediately into saying that "we can't access [transcendent morals]", but this statement alone seems to assume that every religious text in the world that makes any kind of moral statement is false or misleading (and this is far beyond the scope of this thread).
Probably the most interesting part of your paragraph is that
"Absolute morality has nothing to do with humans, and whether or not it exists does not change the fact that morality is subjective for us humans." I think that I must have missed something somewhere, because if absolute morality exists, then clearly the very idea of subjective morality is false. If this is the case, then morality is
not subjective for humans.
Finally, I don't think that the food analogy is valid here (if it is at all, I still haven't made up my mind on that yet). After all, if God exists, then He will be judging everyone by
His moral standard after they die, so it would be far more important for us to find out what His moral standards are than it would be for us to find out what food God likes best (assuming there is one).