Long story short:
Talos was a bronze, mountain-sized automaton from Greek mythology. It was built by Hephaestus - the god of craftsmanship - to guard Europa from pirates.
The Talos PRINCIPLE is a claim that the distinguishing traits of a human can be reduced to mechanical terms, which leads to people wondering if simulated humans are, for all intents and purposes, human.

...so what does this have to do with a laser cannon?