Then, the ask: how can Islam contain an Economic system,...

Then, the ask: how can Islam contain an Economic system, when in our study of Islam, we find that Islam does not include any knowledge of economics, such as indicated by the theories of supply and demand, or the law of diminishing returns, and it does not postulate a law, such as the "Iron Law of Wages"? Nevertheless, we are all aware that the investigations of knowledge of economy only came into existence within the last century or so, since economic investigators like Adam Smith became famous.

The opponents to an Islamic Economy may harbour a wrong impression that Islam originated economics of its own. However, if we distinguish between economics as a branch of knowledge, and Islamic Economy as an ideological system, any wrong impression can be corrected. Furthermore, this clarification would mean that Islamic Economy does not necessarily reflect the economic laws of supply and demand in a control-free economy.

What Islamic Economy can offer is a specific program for regulating the socioeconomic conditions in a manner harmonious with its ideology. We will further discuss Islamic Economy in detail in this book bringing in perceptible reasons and aims given in Islamic traditions. However, the easiest way to prove the existence of something is to make it readily perceptible.

Before we offer the proof of the existence of a socio-economic ideology in Islam, we will only state one reason for its existence, which is derived from the ideological comprehensiveness and structural integrity of Islam so that a broad understanding of the Shari'a (Islamic laws) is required. One basic and inseparable feature of the Islamic laws (the Shari'a) is their comprehensiveness and applicability to practically every aspect of human life.

The comprehensiveness is derived not only from the Islamic Commandments themselves, but from the practical applications and interpretations in the processes of jurisprudence and in the traditional sources of Islamic knowledge. We may refer to some of these sources now.

Abi-Basir relates about Imam Sadiq (a.s.) that one day the latter was explaining the comprehensiveness of the Islamic laws as imbibed by the knowledgeable members of the Prophet's Household, by saying, inter alia, that Islam has prescribed solutions to human problems encountered in life. Islam has declared certain things to be lawful and prohibited some other. It has prescribed penalties even for a slight abrasion inflicted on a person's body by another person.