Forrest wrote:BloodHenge wrote:pillar_of_hate wrote:I don't agree that systems of morals use different starting points and different reasoning to reach the same conclusions; if anything, they all use common maxims as a starting point, and try to build a philosophical justification for them, usually based on whatever metaphysics they happen to adhere to.
The thing is, that's not how a logical argument is made. What you've described is starting with a conclusion, and then choosing premises from which the conclusion can be deduced. If that is then set forth as a logical argument, it must begin with the premises and end with the conclusion. Each of the philosiphical views you mentioned does indeed use different starting points and different reasoning to reach the same conclusion.
Actually, many practicing ethical philosophers do in fact take common moral intuitions as "evidence", and try to construct a "theory" which accurately "explains" those intuitions, just like scientific theories are constructed to explain given observations. I'm not entirely sure whether I agree with that approach, but it is common amongst professional philosophers, who should know how to argue logically if anybody does.
(Of course, some philosophers of science argue that such confirmationism is just the fallacy of affirming the consequent - saying "P entails Q, and Q is true, therefore P is true" - and I actually kinda side with them a bit...)
What I was trying to say, and apparently failed, is that the premises and the logic are fit to the conclusion. Even though the metaphysics is logically prior, it is created last in temporal terms, after ethics and morality. If I came up with a set of metaphysical axioms, and showed you a sound argument depending on those axioms that proved that it was a moral obligation to exterminate Jews, you would reject the whole system. Philosophers do, and have done, likewise.
For example, consider the Epicureans. They argued that the point of life was pleasure, and you should do everything to maximize your own personal pleasure. However, they rejected all licentious forms of pleasure by stating that any behavior that can have unpleasant consequences should be considered in light of its consequences, not independently of it. This mean no orgies, no thrill-seeking, no blood-thirstiness, and so forth, and made Epicurean philosophy on par with the "everyday morality" of the Hellenistic world, which espoused moderation.
Some of the French po-mo existentialists (most notably Levinas) have tried to adopt a philosophy where ethics is logically prior to metaphysics, but their tracts are very poorly written.