||The thesis of this work is to enlighten the process of decision making of an individual in time, which is in the end integrated into market system, where many individuals, who are deciding simultaneously, interact together,. The fundamental principles of decision making contained in this work are drawn from the work of G. L. S. Shackle, which chief characteristics are instantaneousness and uncertainty caused by the lapse of time. Hence, the decision making of an individual takes place in the specific instant through generation of conceptions about possible future outcomes of action. The generation of these concepts is based on instantaneous and apriory conceptions, which represent the description of the working of system. Further decision making consists of application of expectations and assignment of future value to the imagined outcomes. As every individual lives in a society comprised of a large number of individuals, diffusion of knowledge and expectation takes place by means of realization of plans and price mechanisms. Thus, every individual achieves to gather sufficient amount of knowledge to be able to make meaningful decisions in this complex system, which is changing in the lapse of time.