system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: When we talk to ourselves inside our head, what's happening? Why do we "hear" a voice even though no sound is being produced?
gpt
Okay,  so your brain has never experienced sound directly. Your ear receives sound and converts it into electrical impulses which gets sent to and interpreted by the brain as sound. In fact all your sensory organs do this. Your eyes receive light and convert it into electrical impulses,  your tongue and nose receives chemicals and converts it to electrical impulses and your skin does the same thing with touch. Your brain takes all this input and generates a "reality" with it but has never experienced "reality" directly. When you "hear" your voice in your head your brain is doing the exact same thing it would be doing if it were interpreting sound externally. It's generating a "reality" of sound. This is also what is happening when you are dreaming.  Your brain is generating a "reality" of your dream in precisely the same way it would if you where awake minus the electrical impulse stimulus.