It's easy to get 50% by flipping a coin or rolling a die. Choosing to use this method is an example of free will overcoming determinism. As far as why humans

It's easy to get 50% by flipping a coin or rolling a die. Choosing to use this method is an example of free will overcoming determinism. As far as why humans are natural pattern-generators, music is illustrative. If timing and frequency are random, that's not enjoyable music. Probably has something to do with resonance and the fundamentals of neuron biochemistry, e.g. the neuronal recharge time after firing, etc. This seems to be a general feature of evolution, look at squid color patterns or reproductive timing in algae and so on. It's probably a fundamental feature of all living systems, and could be linked to astronomical phenomenon, orbital parameters and light/dark cycles, and even down to subatomic processes, in which oscillation is always going on - but at this level, true randomness seems to exist in various processes like the timing of nuclear decays in a sample of matter. This inherent randomness at the root of everything seems quite real - hence, free will exists. I guess.