If an entire process is understood, the next step which is taken by the process can be calculated. For example, if we were to measure the force of which the human hand applied to a die as well as the angle at which it were launched, factored in friction etc and all "hidden" variables (those which we are not aware of), we would be able to determine where the dice would land and which number it would face up.
If the same concept is true for chemical reactions in our brain, and virtually every reaction in our universe, does fate exist? I.e if we froze time and measured all factors in our universe, would we be able to calculate what occurs in the next time frame?
Quantum Mechanics suggest that randomness does exist; though Einstein himself (after discovering it) spent his entire life trying to disprove this, as he himself did not believe that randomness did exist. However most scientists believe if randomness does exist, is at such an insignificant level that it is not considered to affect large systems at a macroscropic level.
Neuroscience of free will - Wikipedia, the free encyclopedia
Benjamin Libet also proved that our brain responds to muscle movements before we make the continuous decision to move these muscles. I.e, when we move our fingers, we haven't yet continuously decided to do so. That infact, we only become aware of this movement several moments after our fingers begin moving.
So watchu think? I believe fate exists, but I also don't give a shit that it does. For example, I'm okay believe god doesn't exists, because otherwise, when I am dead, I cease to exist and am not alive to experience death.