In modern epistemology, empiricism and rationalism are opposed by emphasizing sense experience and knowledge by reason, respectively, and Kant critically synthesized this opposition by dividing human perception into sensibility and reason, and arguing that true knowledge is formed when these two elements are combined.
Humans are knowledge seekers. Our lives can be seen as a continuation of the process of seeking knowledge, from the mundane to the specialized. One branch of philosophy that systematically examines this knowledge is epistemology. The problem of epistemology was discussed in ancient times by the Sophists, Plato, Aristotle, and others, but it was only in modern times that it emerged as a central issue in philosophy. This is because the question of knowledge became important as modern philosophy demanded certainty, such as natural scientific knowledge. Modern epistemology can be broadly divided into empiricism and rationalism.
Empiricism, which developed in England in the 17th century, considers only knowledge gained through sensory experience and believes that all knowledge can be derived from human experience. They did not recognize as knowledge anything a priori that cannot be known through sensory experience. Empiricism relied heavily on inductive methods to gain knowledge. By observing and verifying individual phenomena, they tried to find common features or identical relationships, and then formulate laws or concepts based on them. However, the inductive methodology is inherently flawed, just as the whiteness of swans in Europe does not mean that swans around the world are white.
On the other hand, the rationalism that developed in continental Europe did not consider individual facts obtained by the senses to be knowledge because they were subject to change. They believed that knowledge is eternally immutable and that we should seek universal truths. This was thought to be possible only through reason, and therefore, reason was considered the most ideal form of knowledge. Reason refers to the innate ability to perceive as opposed to the acquired ability to sense. Rationalism sought to derive individual facts from universal principles through the deductive method. However, the problem with this approach is that it neglects sensory experience and physical reality, ignoring knowledge of concrete reality and failing to provide adequate explanations for the discovery of new facts.
In response to the opposition between empiricism and rationalism, Kant proposed a new system of cognition that could overcome it. Kant divided our cognitive faculties into the senses and the five senses. Sensibility is the ability to make sensory intuitions from stimuli (sensory data) coming from the outside world, and the five senses are the ability to conceptualize based on sensory intuitions. Kant believed that knowledge should have content and form. Content refers to sensory experience, and form refers to the five senses. Kant believed that stimuli from the outside world are ordered through the senses, and the five senses organize them into categories to form knowledge. In this way, Kant critically accepted and synthesized the problems of empiricism, which relies only on sensory experience, and the problems of rationalism, which excludes sensory experience.
