Scott Alexander wrote this review of Julian Jaynes’s The Origin of Consciousness in the Breakdown of the Bicameral Mind, which presents a fascinating idea about when the “theory of mind” emerges in human history. When did human beings realize their emotions, beliefs, and knowledge were internal to themselves, and not spiritual injections from the gods or voices of disembodied forces?

The book makes the claim that there was a turning point in theory of mind perception during the Bronze Age, between 1500 and 750 BC.

As you go about your day, you hear a voice that tells you what to do, praises you for your successes, criticizes you for your failures, and tells you what decisions to make in difficult situations. Modern theory-of-mind tells you that this is your own voice, thinking thoughts. It says this so consistently and convincingly that we never stop to question whether it might be anything else.

If you don’t have theory of mind, what do you do with it? Children don’t have theory of mind, at least not very much of it, and more than half of them have imaginary friends. Jaynes has done some research on the imaginary friend phenomenon, and argues that a better term would be “hallucinatory friend” – children see and hear these entities vividly. The atheoretical mind is a desperate thing, and will comply with any priors you give it to make sense of its experiences. If that prior is that the voice in your head is a friend – or god – it will obediently hallucinate a friend or god for you, and modulate its voice-having accordingly.