Legally, we are already in the posthumanist era. Corporations have long been considered persons in certain jurisdictions, despite not facing the same potential limitations on their freedom as actual people. A couple of years ago, a stretch of the Magpie river in Canada was also granted legal standing as a person, as part of an attempt to provide it with environmental protection.
And now, the “most invasive animals on earth” have also been elevated to personhood, the late Pablo Escobar’s hippos.
Ordinarily we understand posthumanism to be some sort of utopian merging of man and machine, but perhaps it might also, and better, be understood as a way of treating non-human entities with the same respect generally extended to humans.
Of course, I feel that implementing human rights (and responsibilities) for all humans might be required as a priority. We’re at risk of stratifying the world into a place where non-humans have more rights than some humans.
Which is the fundamental problem with posthumanism as a utopian ethos. Like all utopian ideals, it is utterly blind to the stratification it ushers into being, even while denying it is doing so.