Why did John Locke reject the idea that humans are born with innate ideas?

John Locke rejected the doctrine of innate ideas in his Essay Concerning Human Understanding, arguing instead that the human mind begins as a tabula rasa, or "white paper," void of all characters.12

His rejection was based on several key arguments:

• Lack of Conscious Awareness: Locke maintained that for an idea to be "in the mind," one must be conscious of it. Because infants show no evidence of possessing complex moral, logical, or mathematical truths, he argued it is an unwarranted assumption to claim these ideas are imprinted at birth.2
• Empirical Observation: He pointed to the diversity of human belief across different cultures. Travelers’ reports of societies lacking concepts of God or holding vastly different moral standards suggested that these ideas are not universal or innate, but rather products of experience and environment.2
• Origin of Knowledge: Locke proposed that all "materials" of reason and knowledge are derived from two sources: sense experience (external objects) and reflection (the mind's awareness of its own operations).12

By clearing away the "intellectual rubbish" of innate principles, Locke sought to establish a foundation for knowledge rooted entirely in human experience.2