This article is an excerpt from the Shortform book guide to "Determined" by Robert Sapolsky. Shortform has the world's best summaries and analyses of books you should be reading.
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Is free will real or just an illusion? Could quantum mechanics hold the key to understanding our ability to make choices?
In his book Determined, Robert Sapolsky picks apart arguments in favor of free will. He even dives into the fascinating world of subatomic particles and their potential impact on human decision-making, as some people believe there’s a connection between quantum indeterminacy and free will.
Read more to understand the issue and Sapolsky’s arguments.
Quantum Indeterminacy and Free Will
In his book, Sapolsky addresses the concept of quantum indeterminacy. Free will, some say, is made possible by quantum mechanics. Subatomic particles such as electrons and quarks, which—for reasons that even the world’s top physicists don’t yet understand—behave according to completely different rules from larger objects. Some people believe that those rules, collectively called quantum mechanics, make free will a possibility.
Specifically, quantum indeterminacy states that a subatomic particle’s behavior at any given moment is not the result of what happened the moment before. Scientists have observed this in numerous experiments with subatomic particles; identical starting conditions can produce different results, which overturns a fundamental point of determinism.
Therefore, it seems that subatomic particles aren’t bound by the same deterministic laws that larger objects are. So, the argument goes, could it be said that those particles are choosing how to behave? And doesn’t that suggest that people—who are, after all, made of such subatomic particles—might be able to do the same?
(Shortform note: Quantum indeterminacy is closely related to what’s commonly known as Heisenberg’s Uncertainty Principle. This principle states that at the quantum level, there are certain pairs of properties that can’t be known simultaneously. The classic example is that it’s impossible to know both the speed and the location of an electron. This is because these subatomic particles also have properties of waves, which don’t exist at one fixed location; by definition, a wave cannot be a single point. It’s crucial to note that this uncertainty isn’t a failure of measurements or calculations, but rather a reflection of the fact that—due to their dual nature as both particles and waves—electrons don’t have fixed speeds and positions. In other words, their behavior is indeterminate.)
Arguments Against Free Will Via Quantum Indeterminacy
As with the other theories we’ve discussed, Sapolsky has several arguments against the idea that quantum indeterminacy makes free will possible.
The first flaw in this theory is right in the name: The particles’ behavior is indeterminate. This means their actions aren’t being controlled (which is to say, determined) by any other force, including the force of will. So, even if quantum mechanics do allow for multiple courses of action arising from the same starting point, it still wouldn’t be you choosing which course to take.
This brings us to the second problem: Quantum indeterminacy is random. Scientists know this because, while they can’t predict exactly how subatomic particles will behave, in some experiments they’ve been able to predict how likely each possible outcome is. Therefore, if your free will were fueled by quantum indeterminacy, then your actions would also be random, and that’s obviously not the case.
To illustrate the point, you can compare the randomness of subatomic particles to the randomness of rolling dice. For instance, if you roll two six-sided dice, there’s no way of predicting exactly what total you’ll get—but you can calculate the odds of each result fairly easily. However, human behavior is much too focused and purposeful to be the result of subatomic dice rolls.
Finally, Sapolsky explains that quantum indeterminacy cancels itself out on the macroscopic scale (anything big enough to see with the naked eye). This is because there are an incredible number of indeterminate quantum events happening at any given time, so they all average out; for each particle that randomly moves, another particle randomly moves in the opposite direction, and the net impact of those movements becomes zero. It’s incredibly unlikely that enough particles would randomly behave the same way to influence even a single one of your neurons, never mind controlling your entire brain for your whole life.
| How Computers Benefit From Quantum Mechanics It’s unlikely that quantum indeterminacy has any effect on human thought. However, some modern computers do take advantage of quantum mechanics to “think” much more quickly than traditional computers can. The uncertainty principle—which gives rise to quantum indeterminacy—means that these quantum computers can calculate many different possibilities at the same time. This is possible because quantum computers use a different basic unit of information than traditional computers do. A traditional computer runs calculations using bits that can only exist in one of two states at any given time; we might call these states A and B. So, to determine all possible outcomes of a complex situation, this computer would have to set the relevant bits to A and calculate the result, then flip one bit to B and recalculate, and so on. Quantum computers, on the other hand, use qubits that can exist as both A and B at the same time. Therefore, instead of needing to run separate calculations for each possibility, such a computer can calculate all possibilities simultaneously and then determine which possibilities have the best odds of being correct. This allows a quantum computer to process exponentially more information than a traditional computer could and to do so in a fraction of the time. |
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Here's what you'll find in our full Determined summary:
- Why some people believe we have free will—and others don’t
- Three implications of a world without free will
- Why we should live as though free will doesn’t exist (even if it does)
