Equality in the Rawlsian sense is not possible in Islam. In Islam, the elaboration of equality from the original position would tantamount to heresy. It would mean that denominators like gender, sexuality, religiosity or social role (as a spouse or a parent) would not be taken into consideration. Equality regardless of things like sexuality and religiosity in other words. This could fatally result in the possibility of gender equality, the abolition of homophobia and secularism (in that from behind the veil of ignorance, there would be no religious adherence). Who would want that?
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I think I have a clue on why this acute topic for comparative studies haven't been subjected to more attention by people a whole lot more merited and knowledgeable than you and me. Firstly and most obviously, because there is no real concept of equality in Islam, other than the value of a human life. There seems to be some kind of equality there, although not consistent. And secondly, because a comparative study, done honestly, would be so conclusive in the unfavorable direction (for the moral relativists of the Western world) that there is no concept of equality, not even remotely a concept of morality in islam, other than the wishes and urges of a megalomaniacal God. No religion with a consistent and comprehensive morality (let alone a timeless one) would allow the ownership and abuse of a 9 year old, for example.
But how many intellectuals with the rigor of intellectual honesty could you count with your fingers? And the corollary is, how many cowards who take upon themselves and their frontier the chains of political correctness do you know of?