I have also just recently re-read one of Terry Pratchett's Science Fiction novels, The Dark Side of the Sun. Its message is one that I have always struggled with when it was presented as a more explicit claim: there is no objective view of reality, instead we cannot avoid having a subjective perspective depending on our identity. The scientifically most advanced alien species in the book have realised that they have hit the limits of what they can figure out, and so they try to gather insights from other intelligent species. The Creapii go as far as to recreate the natural environment of other life forms to immerse themselves in it, to try to feel what it is like, for example, to be a human.
This idea that all knowledge is subjective is a very po-mo concept, and I somehow suspect that Pratchett cannot mean it quite to the strictest interpretation. Indeed I can hardly believe that postmodernist scholars can really mean it like that. A water molecule consists of two atoms hydrogen and one atom oxygen. If a Creap, a Phnobe or a Drosk - three types of alien from the novel - examine water, would they find it to consist of three hydrogen atoms instead, or perhaps to contain plutonium? Surely not. Instead of “it has two atoms of hydrogen” they might say “sldjlkjs lksjf l slkfdj lsj fs”, but once we clarify all the definitions and translations we would expect to arrive at the same number of atoms of each kind, because that is just what is observable out there in nature.
By extension the same goes for everything that can be tested or examined empirically. There should be no female or male astronomy, no Jewish or Aryan physics, because the stars are the stars and the Theory of Relativity is either a good description of reality or it isn't.
What there is, if anything, is the good old “what it is like to be a bat” question. In an important sense, we humans will never know what it is like to be a bat, and I will never know what it is like to be a woman. All we can do is contemplate things at a purely intellectual level, such as that bats use echolocation and that women can (usually) become pregnant, but how any of that feels I at least will never be able to truly appreciate.
But there are two things to be considered here. The first is that this is perhaps somewhat regrettable but not really crucial. It is much more important to know the stuff that we can indeed figure out as objective knowledge, the kind of stuff that allows us to heal diseases, build working machines and improve our agriculture, than to know how if feels to be somebody or something that we just plainly aren't.
The second is that it cannot be helped anyway. Even the super-advanced aliens of Pratchett's story must ultimately make do with asking other species about their views. The book ends with everybody talking, listening, exchanging perspectives. And that seems to be all that is really needed.