The construction of scientific knowledge involves a long path in which different levels of abstraction are linked, certain methodological principles are fulfilled and various stages in the process of investigation of phenomena are covered in order to achieve at the end of the path an objective knowledge, that is to say, one that corresponds to the reality being studied. The process of knowledge begins when the sense organs come into contact with the external world. Common knowledge. Everyday. also known as empirical – spontaneous, is basically obtained in this way through the practice that man performs daily, which has allowed humanity to accumulate valuable and varied experiences throughout its history, the acquisition of scientific knowledge requires, instead, the joint activity of the sensory organs and thinking of the cognizing subject, supported by theoretical reflection and guided by a series of principles and rules in order to discover what the empirical – spontaneous knowledge can not capture: the essence of the processes, events and object.