Is free will possible in the Universe because of human beings?

It is often inherently impossible to understand the interaction of the multitude of causes that appear to trigger a specific observable effect. Thus, even if a causal relationship exists in nature and is recognizable as such, knowledge of the specific cause/effect relationship might not necessarily result in the ability to project or forecast complex events accurately. This fact is evident in the stock market, where concurrent interactions of billions of people manifest themselves in price fluctuations.

Limitations on possible numbers in the universe make it inherently impossible to ask several billion people, instantaneously, what their investments decisions are at any given moment. However, the motivations and interactions of all these individuals result in the observable effect of market fluctuations. For practical purposes, this deviation from causality due to untraceable causes renders the stock market essentially unpredictable.