I've explained that- it comes from our brains. We have developed and learned to reason in order to make sense of our surroundings. Having developed that and refined it, we developed logic to make reason more reliable.
How do we know it is reliable? Because those have allowed us to make sense of our world and shape it to our needs. Logic itself is based on simple steps similar to the scientific method: observe, hypothesize, experiment, and so on. The results demonstrate its reliability.
I'm guessing that you're never going to answer my questions.