Well, this will be my fourth post for the day, so I shall shut up after this.
I think there is a historical/socio-economic explanation, and it applies to the Ancient Greece of Aristotle as well as the medieval Europe of Thomas Aquinas, all of whom agreed with the Prophet Muhammed (who, btw, was the only founder of a major world religion to have been a practicing merchant). These were predominantly rural societies. Generally in any village there would be one or two moneylenders. When did they make lots of money? During famines when villagers were desperate to borrow merely to survive. The monopoly moneylender could then get away with charging "usurious" interest rates in triple digits, etc. Unsurprisingly, such practices were not regarded as moral at all, and explain the vehemence of the denunciations of interest (riba) one finds in the Qur'an.
But profit was not seen as quite as exploitative of helpless starving people. The receiver of profits was seen as bearing risk in contrast with the recipient of interest.
Modern Islamic economists have made interesting efforts to defend on modern economics grounds the forbidding of interest. Some have emphasized anti-colonial and anti-exploitative themes (the more pro-socialist branch). Others have argued that this will be more macro stabilizing as borrowing for speculation will be blocked (!). Opponents argue, natch, that there will be insufficient savings. This is a long argument.
BTW, of course once receiving interest was declared to be sinful, as it was in Islam and Roman Catholicism, it is unsurprising that moneylenders tended to come from religious minorities who then received the stigma and condemnation of the majority. Barkley Rosser On Wed, 26 Aug 1998 14:51:11 -0400 Carl Remick <cremick at rlmnet.com> wrote:
> Re Barkley's: A major question regarding Islamic economics is the
> extent to which it favors socialism or capitalism.
>
> Is there any Islamic rationale as to why interest is forbidden but
> profit and inheritance are OK, or is this simply a matter of revelation?
>
> Carl Remick
>
-- Rosser Jr, John Barkley rosserjb at jmu.edu