The starting point of the theory of knowledge ought to be ordinary daily experience, the universal and natural certainty of human beings concerning the objectivity and truth of their knowledge. After all, it is not philosophy that creates the cognitive faculty and cognition. Philosophy only finds it and then attempts to explain it. Any solution that does not explain the cognitive faculty but instead destroys it and, failing to understand cognition, turns it into an illusion, is judged by that fact. Only a theory of knowledge such that on the one hand it never leaves the ground of experience and on the other penetrates the very depths of the problem has a chance to succeed. Tertullian rightly says: First there was man, then the philosopher or the poet. One must first live, then philosophize (Primum vivere, deinde philosophari). Natural certainty is the indispensable foundation of science. Scientific knowledge is not a destruction but a purification, expansion, and completion of ordinary knowledge. Every human, after all, accepts the reliability of the senses and the existence of the external world, not by a logical inference from the effect, in this case the representation in his consciousness, to the cause outside of himself, nor by reasoning from the resistance his will encounters to an objective reality that generates this resistance. Prior to all reflecting and reasoning, everyone is in fact fully assured of the real existence of the world.
This certainty is not born out of a syllogism, nor is it supported by proof; it is immediate, originating spontaneously within us along with perception itself. It is not a product but the foundation and starting point of all other certainty. Every human, even the least knowledgeable, a child already and an animal also, accepts in advance, without any reasoning, the existence of an external world.
— Herman Bavinck, Reformed Dogmatics vol. 1, 223
