system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: If transistors in computers act to switch off or on the flow of electricity, what mechanism acts to "decide" whether it should be switched?
gpt
Other transistors.

Yes, this sounds circular, and it sort of is. At the very "start" of the system (I.e. startup) there are some circuits which are not controlled by transistors and are hard coded to do specific startup actions; but from there it's all controlled by some transistors signalling others to switch, which signal others etc. and coming back round to the original ones at some point.