F. Prokopovich's rationalism especially brightly came to light in the logical doctrine. The central element the judgment - a product of activity of intelligence admitted. Judgment - a result of the rational act of the knowledge which is made on the second - logical - its. All logical means are connected with judgment. Logic science of achievement of truth, the tool of its formation as it is about process of thinking.
This discrepancy is caused by that Prokopovich on-noyovomu understood purpose of philosophy. It was estimated by it not as esoteric knowledge for certain philosophers, but as means of satisfaction of the corresponding inquiries of a considerable circle.
Considering a ratio of two stages of knowledge, F. Prokopovich warned that at a stage of sensory perception it is impossible to. To be in the power of the feelings is means to remain always in captivity most often of the bad habits and the lowest destroying sense organs of the person, his mentality, breaking normal activity of the person.