Rationalism and empiricism were two philosophical schools in the 17th and 18th centuries, that were expressing opposite views on some subjects, including knowledge. While the debate between the rationalist and empiricist schools did not have any relationship to the study of psychology at the time, it has contributed greatly to facilitating the possibility of establishing the discipline of Psychology. This essay will describe the empiricist and rationalist debate, and will relate this debate to the history of psychology.
The debate between rationalist and empiricist philosophers looks at the nature of knowledge, and specifically, how we gain this knowledge. Rationalists and empiricists take opposite, and sometimes mutually exclusive, views on how knowledge is obtained.
Rationalism is based on the assumption that all human beings are innately rational. French and German rationalist philosophers, such as Decartes, Spinoza, Leibniz and Kant believed that basic metaphysical questions can be answered by reason alone. In his work Discourse on the Method, Decartes attempted to arrive at a set of principles that are fundamental, and in this way to arrive at true knowledge; to do that he methodologically rejected everything that he can doubt. Decartes summarised his conclusion in saying “I think therefore I am” (Decartes, 1637); he concluded that only thought exists, and because thought could not be separated from him, he also concluded that he exists. This conclusion that only the existence of thought cannot be doubted led to the view that reason and thought are the nature of the soul, and that humans are basically rational, is the foundation for rationalist thought. According to rationalist philosophers, reason is what separates humans from animals; reason was seen as innate. Reason was seen as being separate from the senses. An important quality of reason was that it could be studied. Philosophical schools were beginning to view ideas in a scientific light, valuing the ability to study them. This was moving closer to allowing for the establishment of a discipline which studied humans scientifically.
Another idea postulated by continental rationalist philosophers is Cartesian Dualism: that the mind and body are two separate entities; the body is a biological mechanism hat works like a machine, following laws of nature (Decartes, 1647), while the mind, or soul, is a representation of God. The mind and body interacted, according to this view, in the pineal gland in the brain (Baldwin, 1913). This view was important in the development of science that led to the establishment of psychology, because previously it was not possible to discuss the soul philosophically. However, the dualist view separated human, animal and vegetative souls into a hierarchy, and so humans were still viewed as being beyond the realm of science. A similar idea to the hierarchy of souls was described by Leibniz (1714) in his Monadology, he described a hierarchy of existence,...