Muslim economists have employed the mainstream economics tools to explicate consumption in the Islamic framework. Two of the key limitations of these early works are that they used the Keynesian framework without building micro foundations and they did not model the behaviour in an intertemporal context.
There is considerable debate in Islamic economics literature on what shall be the correct response and attitude towards mainstream economics methodology. There are three varied responses among Islamic economists regarding the issue. The first response is to use the methodology of mainstream economics in Islamic economics as is. The second response is to modify it according to the needs and the context of Islamic framework. The third response is to discard it altogether and devise a new methodological framework from scratch.
The difference in an Islamic framework would come with the normative distinction between investments which are declared as prohibited in the ethical injunctions of Islamic faith and other investments which are deemed as permissible.
Islamic Economics Project 