The standard LW position (which I think is probably right) is that human brains can be modelled with Turing machines, and if that is so then a Turing machine can in theory do whatever it is we do when we decide that something ls liberty, or pornography.

There is a degree of fuzziness in these words to be sure, but the fact we are having this discussion at all means that we think we understand to some extent what the term means and that we value whatever it is that it refers to. Hence we must in theory be able to get a Turing machine to make the same distinction although it's of course beyond our current computer science or philosophy to do so.