In a very real sense, predictions are just your brain having a conversation with itself. A bunch of neurons makes their best guess about what will happen in the immediate future, based on whatever combination of past and present that your brain is currently conjuring. Those neurons then announce that guess to neurons in other brain areas, changing their firing. Meanwhile, sense data from the world and your body inject itself into the conversation, confirming (or not) the prediction that you’ll experience as your reality.
In actuality, your brain’s predictive process is not quite so linear. Usually, your brain has several ways to deal with a given situation, and it creates a flurry of predictions and estimates probabilities for each one. Is that rustling sound in the forest due to the wind, an animal, an enemy fighter, or a shepherd? Is that long, brown shape a branch, a staff, or a rifle? Ultimately, in each moment, some prediction is the winner. Often, it’s the prediction that best matches the incoming sense data, but not always. Either way, the winning prediction becomes your action and your sensory experience.
So, your brain issues predictions and checks them against the sense data coming from the world and your body.
If your brain has predicted well, then your neurons are already firing in a pattern that matches the incoming sense data. That means this sense data itself has no further use beyond confirming your brain’s predictions. What you see, hear, smell, and taste in the world and feel in your body in that moment are completely constructed in your head.
By prediction, your brain has efficiently prepared you to act. When your predicting brain is right, it creates your reality. When it’s wrong, it still creates your reality, and hopefully, it learns from its mistakes: Your brain incorporates the prediction errors and updates its predictions, so it can predict better next time around.
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