From Blank Slates to Natural Selection:
How ideas outside psychology shaped psychological research.
Sonia Valente, 29/09/2026
Are we born with an empty mind, or do our experiences start shaping us right away?
Imagine waking up one day and finding that everything you once knew is gone. You have no memories, no fears, no words, and no understanding of the world. Every face and sound is unfamiliar, and nothing means anything. Your mind is like a blank slate ready to be filled. For centuries, this very scenario has sparked the greatest debate: are we born as a blank slate, or do we arrive with the blueprint already drawn?
The Blank Slate: John Locke
The concept of the “blank slate” (derived from the Latin expression tabula rasa) has been around for a long time in the field of philosophy. However, it became particularly associated with John Locke’s important work: An Essay Concerning Human Understanding (1690). Locke argued that we aren’t born with built-in ideas about the world; instead, he believed knowledge comes primarily from experience, sensation and reflection (Benjamin, 2014). Yet, Locke didn’t think the newborn mind was completely passive. He believed the mind arrived as fully functional software able to receive, organise, and process the world around it, but with no data stored in it yet (Benjamin, 2014).
The Pushback: Reid and Leibniz
Not everyone agreed that we start from scratch. Other brilliant minds, like Thomas Reid (1785/2002), argued that experience alone could not explain how we understand complex concepts like mathematics or morality. Reid argued that the mind possesses built-in common-sense principles that let us understand reality from birth (Benjamin, 2014).
Gottfried Wilhelm Leibniz (1704/1996) offered an alternative metaphor. Instead of a blank slate, he compared the mind to a block of veined marble, where the natural lines and veins represent our innate tendencies and potential. Experience does not simply write on the mind; it sculpts it, chipping away to reveal the shape already hidden inside (Benjamin, 2014). The controversy between these views led to a major split in philosophy between those who saw experience as the primary source of knowledge and those who believed the mind had basic structures from the start.
The Biological Twist: Darwin’s theory
Darwin’s theory of evolution (1859) shifted the nature-nurture debate towards the idea that some human characteristics could be inherited rather than shaped entirely by experience. Darwin proposed that natural selection could shape inherited characteristics across generations, moving the debate from abstract philosophy into biology (Benjamin, 2014).
Nature vs Nurture
The debate didn’t remain philosophical; Darwin’s theory of evolution gave psychologists a new way to think about human behaviour and development. If characteristics could be inherited, psychologists could begin to ask whether other aspects of behaviour had biological origins. This helped shift questions about human nature from philosophy toward empirical research into individual differences, including whether differences in behaviour might reflect both inherited characteristics and individual experience.
References:
Benjamin, L.T. Jr. (2014). A brief history of modern psychology (2nd ed.).
Darwin, C. (1859). On the origin of species by means of natural selection. John Murray.
Leibniz, G. W. (1996). New essays on human understanding (P. Remnant & J. Bennet, eds. & trans.; 2nd ed.). Cambridge University Press. (Original work written c. 1704, first published 1765).
Locke, J. (1690). An essay Concerning human understanding. Thomas Basset.
Reid, T, (2002). Essay on the intellectual powers of man (K. Haakonssen, Ed.). Edinburgh University Press. (Original work published 1785).
