How does empiricism differ from rationalism as a source of knowledge?

In modern philosophy, the debate between empiricism and rationalism centers on the fundamental source and justification of human knowledge.

Empiricism is the doctrine that all concepts and knowledge originate in, and must be tested by, experience. Empiricists generally argue that the mind begins as a blank slate, or tabula rasa, and that knowledge is derived from sensory perception—such as sight, sound, and touch—or through reflection on internal mental states. For empiricists, knowledge is typically a posteriori, meaning it is gained through observation of the natural world.12345

Rationalism, by contrast, maintains that reason or the intellect is the primary source and test of knowledge. Rationalists argue that the world possesses an inherently logical structure and that the intellect can directly grasp certain fundamental truths—particularly in logic, mathematics, and metaphysics—that transcend the limitations of sense perception. This knowledge is often considered a priori, existing independently of experience.126

While these two schools dominated 17th- and 18th-century philosophy, Immanuel Kant later sought to resolve the conflict by proposing that while all knowledge begins with experience, it does not all arise from experience, as the mind imposes its own categories to organize sensory input.156