Rationalism is a philosophical belief that emphasizes reason as the primary source of knowledge. Rationalists argue that certain truths can be discovered through logical thinking and intellectual deduction, rather than relying solely on sensory experience. This approach values the mind's ability to understand concepts and principles, often leading to conclusions that are universally valid. Key figures in rationalism include philosophers like René Descartes and Baruch Spinoza, who believed that knowledge could be attained through innate ideas and logical reasoning. They challenged the idea that all knowledge comes from experience, suggesting instead that some truths are self-evident and can be understood through careful thought.