Rene Descartes: Why Psychology Cannot be a Science Like Physics The philosophies and concepts presented in Rene Descartes' Meditations on First Philosophy illustrate several reasons why psychology cannot be a science like physics. These concepts include that truths are based on clear and distinct ideas, that the mind is not an object but a separate entity, that human psychology is a product of a reflex action between the mind and the body, and that truth can only be obtained by judging ideas based on observing experiments. Each of these concepts will now be looked at in turn, relating it to psychology as a science.

Meditations on First Philosophy is Descartes' attempt to question everything around him and determine what can really be accepted as truth and what cannot. The one sure thing this is based on is that Descartes exists. The reasoning is that if he did not exist, he would not be thinking about whether he exists and so, he must exist. This is captured by the phrase "cognito ergo sum" - I think, therefore I am. Based on this, Descartes accepts this truth and attempts to follow it to see what else he can know for certain. Descartes then reflects on the truths and finds one characteristic that links them all, they are all clear and distinct. Descartes' conclusion is that any truth made up of clear and distinct ideas can be known for certain.

This leads to the first reason that Descartes...

Physics is a clear and distinct science based on definite rules. The laws of physics apply equally to all circumstances. For example, the laws of gravity apply equally to different types of objects and the formulas of physics apply equally to different situations. In short, physics is definite, made up of clear and distinct ideas. In contrast, psychology does not have these clear and distinct ideas. How a person may react to something emotionally is a question of psychology. Unlike physics, there is no rule or formula that can predict the emotional response. Psychology then, lacks the clear and distinct ideas that make it a science like physics.
Descartes' philosophy also distinguishes between the body and the mind, seeing the body as an object and the mind as a thinking thing. The essence of the body is that it occupies space and is flexible, movable and extended. The body is seen as an object, while the mind is not. This is the second reason why Descartes would not agree that psychology could be treated as a science. Science deals with objects. Since the mind is not an object, it cannot be dealt with scientifically.

While Descartes asserted that the mind and body were separate, he also had to accept that they did interact. It is observed that the body impacts on the mind. For example, when you kick your toe your mind registers pain, when you…