Posthumanism is an anti-essentialism and, as such, it rejects arguments from humanity’s intrinsic nature to conclusions about law and morality. Or, at least, that is the logical consequence. It does not stop posthumanists from making ethical and culturally critical arguments that rely on a fluid conception of telos to, somewhat selectively, ground their normative claims. A theocentric posthumanism keeps the anti-essentialism pure, drawing normative commitments from the divine will alone, as I have discussed here and here.
This has practical consequences for engagement by adherents of theistic religions in public debate on bioethical issues relating to human enhancement, genetic modification, and the standing of artificial intelligence and human/non-human hybrids. Those issues are still marginal in the public square, but analogous issues drawing religious commentary in response to advocacy for a secular anti-essentialism are those surrounding transgender identities.
The religious side of the present discourse on transgender issues tends to adopt a two-track approach, arguing from both religious doctrines deriving from purported revelation, on the one hand, and from the statistical promotion of human flourishing, on the other. So, anything sought to be proscribed regarding medical interventions to change gender, and alterations to the rights and duties of transgender people and others who interact with them, is justified by grounding sex and its gender expressions in essential femininity and masculinity, as well as in the teachings of one or more religions.
I have argued that the natural law track is false as a matter of fact concerning purportedly objective essences, and that it also leads to insurmountable theodicy difficulties, i.e. the problem of evil and suffering. However, apart from this, there are two dialectical problems that arise from adopting the two-track approach. Firstly, it generates suspicion that the arguments of religious types from natural law are disingenuous, in that they are really just arguments from religious doctrine cloaked in a discourse more acceptable to a secular audience. This is often a justified suspicion, because medical science and genetics are interpreted selectively to line up conveniently with doctrines and conceptual divisions of the adherent’s religion. On my view, this is to be expected, because there are no intrinsic conceptual divides that justify essentialism about binary gender or humanism, only concepts in the mind of God.
The second problem is the reverse consequence of religious doctrines and conceptual divisions being reinterpreted to align with normative principles perceived to arise from a secularised medical discourse of health and well-being. The first produces a credibility problem with the general public and the second a credibility problem with more switched-on members of the broader community of religious adherents.
Recourse to the two-track approach is understandable, because arguments from religious doctrine are not going to be entertained seriously by the majority of a secular audience. However, I think that the reasons above against the two-track approach are conclusive, and the emphasis should shift to educating the public about the full array of consequences that flow from adopting a consistent anti-essentialism without the constraint of a revealed divine will. This form of argument is often lampooned as the slippery slope fallacy, and unreasonably changing the subject of debate, but that merely suggests the need to focus on broadening the public discourse towards acknowledgement of the social drift towards a continual breaking down of further moral boundaries as an inevitable consequence of anti-essentialist theory.
Theocentric Posthumanism 