John Locke argued your mind was born completely blank, without any innate ideas
In 1689, English philosopher John Locke challenged the popular belief that humans enter the world equipped with innate moral or mathematical truths. In his Essay Concerning Human Understanding, Locke compared the newborn mind to a tabula rasa—a blank slate or empty piece of white paper. He argued that every idea, concept, and memory you will ever possess is constructed entirely from sensory experience and subsequent internal reflection.
The Assault on Innate Ideas
In the late seventeenth century, intellectual life across Europe was dominated by the view that human minds arrive in the world pre-loaded with fundamental truths. Continental rationalists inspired by René Descartes, alongside English thinkers like the Cambridge Platonists, maintained that certain logical maxims and moral principles were divinely stamped upon the human soul before birth. These innate truths were thought to explain how people could recognize basic axioms of geometry, perceive logical consistency, or distinguish right from wrong without needing to derive every principle from scratch.
John Locke set out to dismantle this consensus in Book I of his 1689 masterwork, An Essay Concerning Human Understanding. Locke began by scrutinizing the primary justification offered for innate ideas: universal consent. Proponents argued that because everyone ostensibly agrees on foundational principles—such as the law of identity, that whatever is, is, or the principle of non-contradiction, that it is impossible for the same thing to be and not to be—those truths must be innate. Locke countered that such universal agreement simply does not exist.
To prove his point, Locke pointed to populations who clearly lacked these concepts: young children and individuals with severe cognitive impairments. A small child does not consciously know or assent to abstract logical formulations like non-contradiction, yet if an idea were naturally imprinted on the soul, the mind could not fail to perceive it. For Locke, having an idea in the mind necessarily meant being conscious of it; positing an unperceived, unconscious innate idea was, in his view, a direct contradiction in terms.