The great philosopher Descartes is considered the founder of modern rationalism. According to the model, the mind is not familiar with the objects themselves but only with their copies – ideas projected into consciousness. Descartes starts from the very first truth – from the truth of his consciousness. True consciousness is formed from intuitively self-evident positions. For example, a person intuitively and unmistakably knows that the concepts of day and night do not coincide. Everyone has this knowledge intuitively; therefore, it is true.
Descartes tried to look to the future but always remained focused on old metaphysical and religious questions, such as the nature of the soul. The object of rational psychology is the thinking substance or soul. In a broader sense, Descartes developed the theory of the equality of soul and body (dualism). Thus, according to the philosopher, two principles coexist in a person, rational (consciousness) and existential (soul).