In Western philosophy, traces of the idea that came to be called the tabula rasa (or, that all people are born as a blank slate) appear as early as the writings of Aristotle.
In the 11th century, the concept of tabula rasa was developed more clearly by the Persian philosopher, Ibn Sina.
Tabula Rasa is also featured in Sigmund Freud's psychoanalysis.

But! Aristotle is the first recorded to bring forth such an idea.