In order to accurately understand how Kant bridged the gap between the rationalist method of understanding and knowledge and the empiricists, you must first separate and define the two. .
The rationalist point of view stemmed from Plato, and was acclaimed by many other great philosophers such as Descartes, Spinoza and Leibniz. They believed that reason alone is the ultimate source of knowledge. They believed that all truths could be obtained through a prior knowledge, or innate knowledge. They felt that the world of sense experience is not the real world at all. The only way to see true reality is through reason. A prior defines faculty. .
The Empiricist point of view claims knowledge depends on sense experience. After advances in science, particularly Newton's success in physics, philosophers such as Lock and Hume gained increasing potency to their empirical beliefs. They believed science is the most concrete tool for discerning the intricacies of knowledge. Kant developed an elaborate theory combining parts of rationalist and empiricist trains of thought. .
Originally Kant began as a rationalist, but after reading Hume, he felt enlightened and accepted the idea that all of our knowledge begins with experience. However, he disagreed with Hume when he claimed that all of our knowledge arises from experience. Kant's keen intellect was able to discern the highlights of both points of view and concluded on the notion that there is something determinate in the mind that causes us to know what we know. Combining both points of view, Kant argued that the mind, (being quite a powerful and overwhelmingly intricate device), was able to associate and categorize interpretations of experiences into separate categories, (such as the Transcendental Table of the Pure Concepts of the Understanding) and interpret them through "constructive mechanisms" of the mind. .
Until Kant, it was understood that our knowledge must conform to the objects in which we perceive.