How did Cartesian rationalism differ from empiricism?

Cartesian rationalism and empiricism represent fundamentally different approaches to the origin and validation of knowledge. While empiricism asserts that all concepts and beliefs originate in and must be tested by sense experience, Cartesian rationalism maintains that reason and the intellect are the primary sources of knowledge.12

Key differences include:

• Source of Knowledge: Empiricists argue that the mind is a blank slate at birth, stocking concepts through sensory interaction with the material world. In contrast, Cartesianism posits that certain knowledge is derived through reason from innate ideas.34
• Criteria for Truth: Empiricism relies on observation and experiment, often viewing knowledge as probable due to the fallibility of the senses. Cartesian rationalism, influenced by mathematics, seeks absolute certainty. Descartes rejected reliance on sensation and probability, insisting that only ideas that are "clear and distinct"—free of contradiction—can be considered true.456
• Methodology: Descartes employed a method of systematic doubt to eliminate uncertain beliefs, grounding all knowledge in the bedrock of self-consciousness, or the cogito ("I think, therefore I am"). This approach prioritizes the understanding over the senses, which Cartesians view as indirect and potentially deceptive.546