Idols of the Mind: Francis Bacon and the Science of Learning

The origins of rational error from the father of the scientific method

This week I finished the draft of a book titled ‘Instructional Illusions’ with Paul Kirschner and Jim Heal. The book is about the many illusory biases around learning and instruction and that often, you need to do the opposite of what you think you should do. To address this, we claim that an approach grounded in evidence rather than assumption is necessary to pierce through the many illusions we have in understanding how learning happens.

So one of the things I read in researching this book was Francis Bacon’s The Advancement of Learning and his idea around the false ‘idols’ of cognitive biases. I found it utterly fascinating and also strangely prescient considering what we’ve learnt about cognitive illusions in the last 50 years. This did not make it into the book and was left on the cutting room floor so dear subscriber, I offer it to you here.

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In 1620, Francis Bacon published Novum Organum, a work that would help usher in the modern scientific method. But buried within that text is something even more striking, a primitive theory of cognitive bias that has proven to be eerily prescient. Long before Kahneman, Tversky, or even Hume, Bacon laid out a taxonomy of human error that reads like a blueprint for much of modern cognitive science. Bacon called them “idols of the mind” — systematic distortions that prevent us from seeing the world as it is. He categorised them into four types:

1. Idols of the Tribe: These are errors inherent in human nature itself. Bacon saw the human mind as prone to overgeneralisation, seeing more order and regularity than actually exists. This anticipates what we now know as the patternicity bias; the tendency to see patterns in noise, or to infer causation where none exists.

2. Idols of the Cave: These are the individual biases that arise from personal experience, education, or temperament. We might now call these confirmation biases, availability heuristics, or even motivated reasoning. Bacon recognised that each of us inhabits a “cave” of our own making, filtering the world through its distorting lens.

3. Idols of the Marketplace: Here Bacon anticipates the idea that language is not a neutral medium. Words can entrench misunderstanding, evoke misleading associations, or fossilise bad ideas. In modern terms, this foreshadows concepts like framing effects and semantic priming—the ways in which linguistic cues shape cognition.

4. Idols of the Theatre: These refer to the dogmas of philosophy and received systems of thought. Bacon saw how powerful intellectual fashions could ossify into orthodoxy, limiting inquiry. In today’s terms, this resembles paradigm lock-in or groupthink, where institutions and ideologies resist evidence that contradicts their foundational assumptions.