Is there no choice?

What is choice? Is it only an illusion? Can choice be determined by an observing entity which collectively observes all (related and seemingly unrelated) entities, determining their current state and build a model that treats all entities as a finite state machine? Given a certain set of inputs, an entity can only have one "choice". If so, how does each person become unique? Does that mean fate exists, given that everyone has a pre-determinable destination in life? Mathematically speaking, does this mean that the concept of probability does not exist? If, for instance a unbiased coins' toss is considered, the equal likelihood of heads and tails is associated because the system is improperly modeled. What is everything was taken into account? What if, to model the coin toss, things that need to be observed included coin mass, wind velocity, temperature, humidity, solar flares, tosser's finger configuration, musculature, nervous system, emotional stability, etc

Do we assign probability because we (as humans) are not aware of the variables involved in an event?

Will you regard this blog post and think about it? Do you think you have a choice?