Explain and critique the nature and necessity of interest in the ideas of some economic thinkers in the West

Enter in capitalist economic theory and analysis, decoding and scientific critique of capitalist economists thought, is the first step in the design and implementation of a development model based on Islamic values. Interest is the basis concept in capitalist financial system that in the research explain and critique the nature and necessity of it in the ideas of economic thinkers in the West. Evaluation historical process of usury and convert it to interest in the West shows that until the 13th century the teachings and beliefs of the church's governing and had been rejected interest that accordance with the usury, but dominate the human thoughts without backing to revelation has caused to the detriment of church and in favor of usury change. Eventually led to economic theorists in the West to prove the necessity of interest in economic. In this regard, classical economic theorists, the theory of productive capital and money on the supply side and structure of consumption pattern and time preference for the future on the demand side as the primary theory of positive interest have raised. The criticism that comes from these views is that firstly, in many of the arguments that have been used in the proof of interest necessity, have been confusing the issue and the justification of natural interest means to rate return on capital or profit and not contracts interest rate. Secondly, people's beliefs in valuation and amount of present and future goods play a major role on the demand side that denies origin of interest.