Rationalism (ratio) - reflects a philosophical idea that recognizes thinking (reason) as the source of any knowledge and criterion of its truth. This teaching became popular in the 17th century. The foundations of philosophical views, its traditions introduced Rene Descartes. In his Reflections on a Method, Reflections on a New Philosophy, and other works, the problem of the reliability of knowledge was solved in the realm of knowledge itself and its internal characteristics. This mainly distinguished Rene Descartes’ rationalism from Bacon’s theory of practical solidity.
The first, developing his idea, argued that there are four rules of cognition: methodological doubt, control, analysis and evidence. The rationalism of Descartes established the certainty of the very presence of the knowing mind, the philosopher declared: "I think, therefore I exist." The evidence of this theory, in his opinion, lay in the justification of thinking itself, trust in it. At the same time, God acts as the guarantor of comprehensibility of the created world, as well as the objectivity of human knowledge.
The system of arguments that Descartes cites explains the idea of the presence of innate ideas as one of the basic principles of rationalism. Created things are known only through deepening in the mind. Moreover, all things consist of two substances, independent of each other - body and soul. Moreover, the nature of the body is no more than a mechanism. Strengthening the prevalence of the mind over feelings and bodily passions is an outgoing principle for the search for various formulas of moral behavior in a variety of life situations. This is the concept that Descartes rationalism carries.
It should be noted the great importance of this worldview for the development of philosophy and science. The rationalism of Descartes not only contributed to the formation of new rules and principles, but also formed the basis of some scientific disciplines, in particular analytical geometry, mathematics.
The dualism underlying the idea made it possible to formulate a dual, mutually exclusive interpretation of the doctrine. Rationalism of Descartes provided an explanation of the structure of the world, representing it in abstract and visual images at the same time. The structure of the world assumed the possibility of dividing it (using analysis) into components that would be logically interconnected and mathematically accurately described. This hides the methodological basis of the process of mathematization of natural science.
A rational person with a deductive and intuitive mind can achieve reliable knowledge. The deductive method allows only those assumptions that are clear, clear to the mind - do not cause any doubt in their truth. In addition, within the framework of this method, each complex problem is subdivided into particular, constituting it, periodic transition from known and proved to unknown and unproven, and omissions in the links under study are not allowed.
At the time of Descartes, philosophy attached great importance. Science was considered as the highest value, and the possibility of its practical application in satisfying various human needs increased the cognitive processes of thinking even more.
Influenced by the teachings of Descartes, Benedict Spinoza outlined rationalism using a geometric method. He reflected his ideas in his work Ethics. In this work, each part begins with a clear and simple definition, concept. This is followed by an axiom, a statement with proof. In conclusion, philosophical argumentation is presented.
Spinoza identified three levels of cognition. The first - the highest - implied the comprehension of truth, intuitively visible, directly by the mind. The second level included reasoning that needed proof. The third, lowest level is based on the sensory perception of the world.