Objections to Sartre, and to existentialism in general
I suggested the important ones fall under two headings. One is objections to the assumed Cartesian dualism inherited from the phenomenologists which afflicts all the existentialists and which is the main engine for their philosophical problems. The other is an objection from within the view, that subjectivity as Kierkegaard and Sartre endorse it cannot be made sense of. Admittedly, both families of objections overlap--it may be the problem with subjectivity could be put in terms of problems about whether the notion of mind in K's work results in an impermeable and unintelligible set of private objects.
There are other less important objections and other complaints which may not be objections at all. Iris Murdoch (especially in her book on Sartre but also in several other places, including her _Metaphysics as a Guide to Morals_) suggests the existential notion of an individual is a rationalist bit of romanticism, meaning among other things that the existentialist human being lacks ties to other people, and with those missing ties gone missing is access to a great deal which might provide a source of meaningfulness or value in our lives. Instead, existentialists are required to be heroic just to be alive, and the kinds of heroism of which only the best of us are capable pales in comparison, suggesting that there might be a kind of wishful thinking at work among the existentialists. Constructing a life, constructing values, constructing the world in which we live by way of making decisions filled with angst requires all of us to meet nearly impossible ideals so we can keep living, and thus provides us with a sense of pride in accomplishing something but the accomplishment is an artificial accomplishment which Tolstoy's peasants would find risible. I suggested something like this when I said there is a macho aspect to Sartre. Being alone, which is taken to be a condition of human existence, somehow gets transmogrified into a virtue.
A distinction: the problem about subjectivity is not that it gives license to people to do things which strike us as mad. That is, we mentioned the case of the man in my neighborhood in Eugene who found the meaning of life in luring cats into his yard and killing them, an existential project in which he took pride, and one with some striking resemblances to Camus' Sysiphus. Then we mentioned the case relayed to me by an advisee at Oregon who had worked at Dammasch Hospital for the insane, the woman who for over twenty years dedicated herself fiercely and proudly to the project of opening and closing umbrellas. We are saying what the problem or objection is not. The problem is not we do not understand these projects or that we may have dismissive or contemptuous attitudes toward them--indeed, for many readers of existentialism this endorsement of diversity is a strength of the existentialists. Here's the objection. The problem is that the existential notion of subjectivity makes impossible that there can be a better or worse project, including making it impossible for those whose projects they are to have good reasons for taking on their projects, good reasons to change their projects, good reasons not to do something else instead. We are not talking about external judgments, judgments of other people. We are talking about each person's ability to see that there might be a better or worse project than what we are doing now. If choosing, avoiding bad faith, pride at operating in good faith, deciding to take a leap of faith, choosing to take ownership of our meaning or meaninglessness, owning up to our choices--if any of those are to make sense then they are to make sense as better among worse alternatives. When the woman in Dammasch turned fifty and then began to rethink what she was about, and then grew angry at those who could have helped her consider doing other things, the existentialists can only regard that change in her as an arbitrary change of attitude, certainly allowable to her in her freedom, but not something to which a judgement of better or worse can be based on good grounds. This attitude from the existentialist point of view is just false to her own judgment, which is that she has been wasting her life and that others who saw that could have helped her but did not.