It might seem that everything that’s happening at the higher, ‘emergent’ levels should be uniquely determined by the physics operating beneath them. This would mean that the thoughts you’re having at this very moment were predetermined at the start of the Universe, based on the values of the particle physics variables at that time.
Now you might be forgiven for doubting whether William Shakespeare’s sonnets, Winston Churchill’s speeches and the words in Stephen Hawking’s book A Brief History of Time (1988) really came into being in this way. And you would be right to doubt: there are many problems with the skeptics’ position.
For example, suppose you’re walking down the street, and just in front of you a terrible accident happens – smashed-up cars, people injured, blood everywhere. You react with horror… None of those qualities – sympathy, fear, guilt – occur at the ion or synapse level… In an intricate causal dance between levels in your brain, those thoughts are able to occur because of the underlying spike chains, but it’s their essentially psychological nature – what it means to recognise an accident, which thoughts flow through your mind as you decide what to do, what it feels like to experience the shock of seeing the event – that causes what happens. Physics enabled what took place in your head and body, but didn’t determine it; your mental interpretation of the event did.