Most neuroscientists say thoughts are born from brain cells called neurons. Hameroff suggests the most meaningful action happens at the impossibly small quantum level, where subatomic particles like photons and electrons exhibit bizarre behavior. Quantum physics drives consciousness, he believes.

If Hameroff proposed these ideas himself, he might have been ignored, but his co-theorist was Sir Roger Penrose, an esteemed figure in mathematical physics. Their theory, dubbed “orchestrated objective reduction,” or Orch-OR, suggests that structures called microtubules, which transport material inside cells, underlie our conscious thinking.

But the Penrose-Hameroff model of what you’d call quantum consciousness was a scientific non-starter. Leading experts dismissed the new model outright. Quantum effects, the criticism went, are notoriously difficult to maintain in the lab, requiring ultracold temperatures and shielding to protect against even the mildest interference. Critics said living things are simply too “warm, wet and noisy” to allow significant quantum effects to persist. What’s more, neuroscientists argued, the Penrose-Hameroff model offered no testable hypotheses.

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