Has anyone written a worthwhile utilitarian argument against transhumanism? I'm interested in criticism, but most of it is infested with metaphysical and metaethical claims I can't countenance.
What proposition are you looking for an argument against?
Transhumanism can mean a lot of things: the transcending of various heretofore human limits, conditions, or behaviors - which are many and different from one another.
And for those things, you might refer to the proposition that they are possible, or likely, or inevitable; (un)desirable or neutral; ethically (in)permissible or obligatory; and so on.
If it's worth saying, but not worth its own post (even in Discussion), then it goes here.