فهرست مطالب محمدتقی تولمی

The time value of money is one of the most important issues in economics which is less studied from a jurisprudential and legal point of view. The present money has more value than the future money according to this theory. Some Islamic economists have denied it and others have accepted it. Dissidents of the theory consider its contents as grounds for justification of usury but the supporters of the theory believe that the prohibition of usury is contrary to the theory and is merely a compulsory rule. The source of this disagreement is ignorance of two things in our opinion. First, the monetary value of time and the time value of money are assumed to be the same, and second, that the arguments in the field of probative of theory are not separated from those of its imperative (demonstrative) domain. We have evaluated the validity of the theories’ content in this article by a descriptive and analytical method in addition to explaining the distinction of the monetary value of time and time value of money, on the one hand, and on the other hand we have investigated the extent of its function. There is numerous evidence of jurisprudential and legal doctrines that shows that contrary to common thought, the content of the theory is valid from a jurisprudential and legal perspective, but the study of the extent of the theory indicates that is not possible to make profit and interest by relying on this theory according to the division of economic contracts into for-profit and nonprofit that the time value of money is only in the form of exploitative and profitable contracts such as sale (Arabic: بیع, Bayʿ) and in non-profit contracts such as lending (Arabic: قرض, Qarḍ), which are basically based on benefaction (Arabic: إحسان).

Exchange value is one of the most important issues in economics, which is also considered in jurisprudence under the title of being property by jurists, and in both sciences, various theories about its origin have been presented. The study of common theories of value shows that in these theories, exchange value is looked at with a static view and it is referred to as a point result that is due to causes and factors that are the origin of value at a point in time.In this article, we are trying to prove that the value of exchange is the result of a dynamic, linear and flowing process, which reaches actuality  from potentiality over time through different stages. In this regard, with the introduction of two types of property and exchange value, potential and current, and as a result, the distinction between potential and current property, it is clear that the neglect of the types of value on the one hand and the lack of accurate analysis of the process of value formation on the other hand, have become the source of differences and mistakes in value theories. .

The time value or time price is one of the important issues in economy and financial management whose acceptance or rejection has a significant impact on the analysis of other issues related to the financial markets. Proposing legal reasons, some Islamic economy scholars and theoreticians of Islamic monetary markets have accepted the money value of time and have considered it unproblematic. Some of the most important reasons include the rule of duration (lilajali qistun min al-thaman), the difference between the price of credit and that of cash sales, and the permission of advance payment or discount of the debit. Using a descriptive-analytical method and relying on the jurisprudential and economic sources, this article reviews and criticizes these reasons and shows that first, the theory faces different jurisprudential problems in terms of imagination and second, the reasons of the adherents of the theory are unable to prove the jurisprudential credit of the money value of the time in terms of affirmation.

The theory of legal income was proposed by Shahid Sadr in his book “Ightisādunā”. According to this theory “doing a work” is the source of earning a legal and legitimate income. Reviewing his views specifically in his book “Al-Bank Al-la Rabawi” shows that he has analyzed the issues related to the bank usury based on this theory. This article using a descriptive-analytical method shows that the model of banking without usury has been proposed by Shahid Sadr based on this theory. According to this theory every income earned through the bank must be in exchange for performing an act and superficial changes of the bank contracts and transactions, although they may make an income without usury and illegal profits, since it is not based on doing a work, is illegal and illegitimate. As a result, substituting a loan contract with a contract of sale, muzāriba, juʻālah, and things like this, as long as it does not end to a valuable economic act, will not be the license for making income, and taking or paying the profit and the income and the profit from that will be illegal and illegitimate since it is not based on performing an act.

The juridical rule or principle "duration has a value" is one of the most important jurisprudential principles applicable to transactions and issues such as the option of condition, murabahah sale, tawliyah, muwadha'ah sale, purchase on credit, options, futures or sale of things in advance, usury and loan. Nevertheless, two aspects of the subject e.g. the purport and scope of the rule, have received but very little attention. Two major probabilities with regards to the purport of the rule can be derived from the statements of the jurists. First, the dissimilarity between duration and price and consideration of a portion of the price against the duration in extended transactions. Second, the impact of duration on the amount of the price without them being in contrast with each other.  When it comes to the scope of the rule, a specific criterion has not been mentioned. In this article which uses an analytical descriptive method, the writer demonstrates that according to the rule, duration does have an impact on the amount of the price, and that there is a relationship between the duration and price.  As well, while seeking to present a criterion for explaining the scope of the juridical rule, it is demonstrated that the principle applies to that category of transaction which involves monetary profit or commercial gains. Thus, the principle applies to contracts like sale and lease where the two parties give something in exchange for something else. It is, therefore, not applicable to contracts likes loans. As well, this research will show that after a debt is established on the debtor, it is not permissible for the creditor to increase the amount of the debt, and that the principle of duration does not apply to debts.  It can be said, therefore, that there is objection to some scholars taking recourse to the rule in the area of loans.