People who argue that free will is an illusion have been taught to think that everything about our reality is inevitable, like a long row of dominoes - as soon as you knock over the first one, the rest have no option but to fall over, one after the other.
Here's a link to an article about a new paper published at phys.org, which does a great job of putting this discussion into a broader context: Does the Quantum Wave Function Represent Reality? Let me quote the opening paragraph from that phys.org article, which was written by Lisa Zyga:
At the heart of quantum mechanics lies the wave function, a probability function used by physicists to understand the nanoscale world. Using the wave function, physicists can calculate a system's future behavior, but only with a certain probability. This inherently probabilistic nature of quantum theory differs from the certainty with which scientists can describe the classical world, leading to a nearly century-long debate on how to interpret the wave function: does it representative objective reality or merely the subjective knowledge of an observer? In a new paper, physicists Roger Colbeck of the Perimeter Institute in Waterloo, Ontario, and Renato Renner who is based at ETH Zurich, Switzerland, have presented an argument strongly in favor of the objective reality of the wave function, which could lead to a better understanding of the fundamental meaning of quantum mechanics.
This is a powerful idea, and it speaks to the underlying timeless nature of what we keep coming back to with this project: it shows how there can be Everett's Many Worlds, which is a way of interpreting this quantum wave function which allows for the existence of more than one possible outcome from any position within space-time. We are not dominoes, we are not automatons. And while this doesn't give us magical powers (which is to say, our choices can't violate causality and select an outcome which is logically impossible), we still do have the power to choose one outcome over another within the probability space of possible outcomes. This means medical studies that propose any decision-making process that we perceive as being our free will is really just the result of inexorable electrochemical processes are wrong, because they ignore the underlying quantum nature of our reality. And it means that Martin Rees is correct: even in the big cosmological picture of our universe and of our planet, there are many possible paths we could have traveled to get to "now", and many other possible "now"s that are not even causally connected to the one we're currently observing.
This is true no matter what point in time you are thinking about: there are many possible outcomes, all equally real, and not just the outcome that we happen to be observing right here and right now. Embrace your probability space!
And enjoy the journey.
PS - Just a few days ago, Nature Magazine published an article that also relates very nicely to this discussion: http://www.nature.com/news/a-boost-for-quantum-reality-1.10602
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