It seems to me to found any objective notion of philosophy in general or ethics in particular, you would have to solve the is-ought problem. I see no indication that this has been done or, indeed, could be done. This seems clear for two reasons: one, agreement cannot be reached on the is; two, the ought always implies a value claim. If the equation is; if x then y, then surely the x must be agreed upon if y is to meaningful, objective, or in any way proscriptive. I have to tell you, I just don’t see that happening.
If one makes a claim such as, humans have a primary biological imperative toward survival, therefore we should act in this manner. Here we have an is and an ought. Furthermore, this is a widely held view. But many people simply would not agree upon the is to begin with, and even if they did there could still be wide disagreement concerning how people should act in response to this supposed imperative. I don’t believe that there is any overriding motivation for human behavior. Given how self-destructive humans can be, I certainly don’t believe that there is an overriding imperative toward self, or species, survival. I think people are motivated by countless different things, to the point where I would say it is ‘over –determined.’ Being over-determined, I don’t believe that we can establish an is concerning human needs or motivations. If this is true, then we cannot establish any kind of objective ethics or even objective philosophy. I believe it is hopelessly simplistic to reduce human needs or motivations given how complex society and history appears to be.
The problem is made even more complex when we come to the ought part of the equation. Now, even if you get people to agree to the is, they may disagree with the ought. For example, if people agreed on the idea of an overriding motivation of survival, I think a pretty strong case could then be made that excessive cooperation would be the ought that would follow from this. And given certain evolutionary processes like say, the evolution of canine societies, (which many experts claim is similar to human evolution), then this could be a very strong argument to cooperatives. I am not claiming that it is an open and shut case myself, I am just raising the spectre of reasonable doubt, which is all that needs to be done against any kind of objectivist claim. But even more significant than the simple spectre of doubt is the fact that the ought that people endorse will flow naturally out of their values. This can be seen very clearly when one realizes that people are free to reject any ‘natural’ imperative. Someone may claim that individual survival, for example, is an overriding and necessary instinct to human life, and I might say that I choose to reject and attempt to overcome that instinct. This is just a very simple example that could be applied to any supposed imperative. Ultimately, you can accept or reject a course of action according to you values (and arguably everyone does) which renders, quite simply, any notion of objective action absurd.
Instead what I believe happens is that narrowly define the is and then infuse their ought with a reflection of their own values. In other words, I don’t think that we can define a human nature in anyway that is proscriptively meaningful, therefore we are compelled to imbue our oughts with our own values. It sound very convenient, for example, to say that Humans have a nature, and that they ought to act in accordance with it. But I don’t think we have a definable nature (in any strict or proscriptively useful sense), and even if I did, people could simply say “I don’t think we should act in accordance with it.” And the argument quickly fall apart.
At a slightly more complex level, one might make a proscriptive plan like: All people are compelled to survive, survival demands this kind of action, you ought, therefore, act in this way. Well even if we agreed to the first and second claim (an agreement that I don’t think will obtain) then you might find that some people simply might reject their own survival.