Whether emotion preceded reason or arose concurrently really depends a lot on what you’d be willing to call ‘reason’. That is a definitional quibble. I do think that we– we as in ‘the animals on this planet’– got some very low level information processing long before we got anything like what people think about when they think about thinking. Compare this low level processing to something like instinct or reflexes. Fear, at least in some forms, is a reflex action after all.

Whenever emotion developed just because it was evolutionarily beneficial at one time does not automatically make it so today.

Obviously. The same is true for any other evolved trait you care to name. You are right, ‘good then’ doesn’t mean ‘good now’ but that wasn’t really the point. The point is that emotion did evolve for a reason and chucking it is not something we ought to do lightly.

I wouldn’t base ethics on emotion. Most animals are stuck with an emotional/cognitive soup but we humans aren’t. We humans are the only critter we know of capable of the kind of abstract reflection needed to override some of that mess. We’d be stupid not to.

Whenever emotion developed just because it was evolutionarily beneficial at one time does not automatically make it so today. You compare it to eye sight, but what if it is more akin to the body’s tendency to store reserves in times of plenty. In our past this was a vital survival mechanism that allowed us to survive in lean times. Today in the western world it is just a contributing factor in obesity for many people. I am not putting emotion in either category, I am just pointing out that you have to develop your argument beyond the fact that it was selected for in the past so it is beneficial or even relevant today. Evolution often develops things that loose their usefulness, but still linger on. We could get along just fine without an appendix but would find it rather difficult without a heart (the biological one).

Another problem with basing an ethical system on emotions is that emotions differ from person to person. This would seem to lead to a relativist ethical system. I know how you love those (sarcasm).

A Generation of Damned Relativists