From the previous analyses of both doctrine and science, we have come to know that the doctrine's function is to express the demands of justice, while science assumes the responsibility of discovering the economic events, as they occur, their causes and interrelations.
This difference in the basic function necessarily requires their difference in the methods of research. This means that the science of economics, as such, discovers what occurs in the world and in the society of everything related to the economic life, using the scientific methods of observation and experiment, monitoring the events the economic life is full of in order to derive, in their light, their interrelations and general laws.
Whenever there is a case to doubt, and the extent of its truth and reflections of reality are not known, the economist is capable of referring to the scientific criteria and to his own well-organized observations of successive events in order to discover the extent of the truth of such case and of its being a true reflection of the reality.
Both economist and naturalist are on the same footing in this aspect: When the naturalist desires to find out the degree at which water boils, he can scientifically measure the water’s temperature as a natural phenomenon, observing the temperature when boiling starts.
When the economist desires to discover the sequence of famous crises which inflict the human society from time to time, he has to refer to the events of the economic life as they happened successively in order to determine the historical dividing line between one crisis and another. If he finds such a line to be the same in all crises, he will be able to define the cycle of such crises and in the end look for their causes as well as the factors that affect them.
Contrariwise, the economic doctrine cannot measure the subjects it deals with scientifically because it studies such subjects from the angle of equity and justice, trying to find a regulation method according to the demands of justice and equity.
Obviously, justice is different from the water temperature and boiling degree, and it is different from the economic crises and cycles, because the latter are not cosmic or social phenomena which can be observed subjectively or measured scientifically through the well-known means of experiment in the world. In the economic doctrine, it is not sufficient to look at facts and observe events scientifically in order to know what equity is in organization, as is the case with the economist who studies economic crises in order to know their cycle and code.
Let us take the issue of equity in distribution as an example:
There are some people who say that equity in distribution is achieved in the shade of a system that guarantees equality among all members of the society during austerity as well as during prosperity, and there are others who consider equality of freedom among the members of the society, instead of equality in sustaining them, to be the just basis for distribution, even if individuals practice their free right to variations in sustenance and the increase of the wealth of some over that of others, as long as they all enjoy the same freedom granted equally to each and every one of them.
There are also others who see that the equity of distribution is achieved through guaranteeing a general level of sustenance to all people, while granting them freedom outside the limits of such level, as does Islam.
Can equity of distribution be achieved? Is it equality in subsistence and wealth that matters, or is it the granting of everybody the freedom to practice various norms of economic activity, while limiting each person’s share of subsistence according to the way he practices such freedom? Or is it according to a third method that lies between this and that?
If we want to know the answers to these questions, and to know the approach and concept of equity in as far as these means are concerned, we cannot use science to reach our objective simply because equity is not an external natural phenomenon like temperature or boiling which we can measure by applying our vision or touch or the rest of our physical senses, nor is it a social phenomenon such as economic crises in the capitalist society in order to be evaluated, observed and tested.
Science can surely assess individuals in order to determine the extent of their similarity or dissimilarity in physical or psychological features in order to decide whether it is fair to equate all of them in subsistence or not. Justice and truth are not subjective qualities that can be measured by science or by the senses in the way all bodily or natural phenomena are measured, felt, viewed, etc.
Take the example of the capitalist who believes that people are equal in their right to enjoy freedom even if their shares of subsistence vary, and the socialist who believes that all people are equal in their right to be sustained, and ask both of them this question: “Is there a thermometer for justice like the one for measuring temperature so that I may be able to know the degree of justice in a society where people’s shares of freedom are equal even when their shares of wages and subsistence vary?
Are the ‘rights’ enjoyed by the members of society a natural phenomenon which can be felt as we can feel their own colors, heights, intelligence, voice, etc., in order to study such rights through the use of scientific methods based on the senses or the experiment?”
The answer, of course, to these questions is a plain “No.” Equity has no thermometer because it is not a phenomenon that can be realized through the senses or through observation; nor is the right of people to achieve it one of their own characteristics such as height or intelligence so that we may apply science to determine such right.
The conclusion we draw from this is that as long as it studies the issues from the angle of equity and truth, the doctrine can derive the method it prefers to use in regulating the economic life from its own concepts of equity, from the principles and ideals in which it believes, or from its general attitude towards life.