Blank slate, or tabula rasa (which means the same thing) was a philosophical idea of John Locke. It had, like much of philosophy, a history which went as far back as Aristotle, but it was Locke who made it known to our modern world:
b l æ ŋ k WORD_BOUNDARY s l eɪ t WORD_BOUNDARY ɔ ɹ WORD_BOUNDARY t æ b j ʊ l ə ɹ WORD_BOUNDARY ɹ ɑ s ə WORD_BOUNDARY w ɪ t̠ʃ WORD_BOUNDARY m iː n z WORD_BOUNDARY ð ə WORD_BOUNDARY s eɪ m WORD_BOUNDARY θ ɪ ŋ WORD_BOUNDARY w ʌ z ʌ WORD_BOUNDARY f ɪ l ə s ɑ f ɪ k ə l WORD_BOUNDARY aɪ d iə WORD_BOUNDARY ʌ v WORD_BOUNDARY d̠ʒ ɑ n WORD_BOUNDARY l ɑ k WORD_BOUNDARY ɪ t WORD_BOUNDARY h æ d WORD_BOUNDARY l aɪ k WORD_BOUNDARY m ʌ t̠ʃ WORD_BOUNDARY ʌ v WORD_BOUNDARY f ɪ l ɑ s ə f i WORD_BOUNDARY ʌ WORD_BOUNDARY h ɪ s t ə ɹ ɹ i WORD_BOUNDARY w ɪ t̠ʃ WORD_BOUNDARY w ɛ n t WORD_BOUNDARY æ z WORD_BOUNDARY f ɑ ɹ WORD_BOUNDARY b æ k WORD_BOUNDARY æ z WORD_BOUNDARY æ ɹ ɪ s t ɑ t ə l WORD_BOUNDARY b ʌ t WORD_BOUNDARY ɪ t WORD_BOUNDARY w ʌ z WORD_BOUNDARY l ɑ k WORD_BOUNDARY h uː WORD_BOUNDARY m eɪ d WORD_BOUNDARY ɪ t WORD_BOUNDARY n oʊ n WORD_BOUNDARY t ʊ WORD_BOUNDARY aʊ ə ɹ WORD_BOUNDARY m ɑ d ə ɹ n WORD_BOUNDARY w ɜː l d WORD_BOUNDARY