Is the fact you are reading this story a decision you arrived at it by your own free choice, or was your interest programmed into the universe from the moment of the big bang? What makes free will such a fun topic is not only that it dives deep into physics, neuroscience, and philosophy, but also that we all feel we have a direct stake in the answers. Part of my own interest is that Ive never been able to see why people get worked up about a supposed conflict between free will and determinism. To my mind, there is no conflict. Human consciousness and therefore the concept of free will are emergent properties, so whether microscopic physics is deterministic or not is irrelevant. To speak of a conflict is to mix levels of description. In other words, theres no you who is steered one way or the other by initial conditions. You are a product of those conditions. Ill grant that all this depends on what precisely we mean by “free will.” To me, it is the fact that you make choices. To others, though, free will involves some inherent unpredictability. In that case, it might well have something to do with the deep laws of nature. Within quantum mechanics, there are four basic arguments for such a connection: 1. Quantum mechanics is indeterministic, in that the outcomes of measurements are chosen at random from the slate of possibilities. So, if quantum effects help to shape our conscious choices, they sever the connection between us and the initial conditions of the universe. 2. When we conduct experiments on quantum particles, we exercise our free will—for example, we make choices about what precisely to ask of the particles. Or at least we think we exercise our free will. How those particles respond can depend on whether we really do. 3. If you could predict someone’s decisions consistently, you could conclude that he or she lacks free will. To do that, you’d need to take a full brain scan and simulate his or her thought processes. Yet quantum physics forbids the reliable, nondestructive copying of particles, let alone whole brains. If you could never observe the loss of free will, then you should doubt whether it is ever really lost. 4. Quantum physics is time-symmetric, so we are as justified in saying that our choices set the cosmic initial conditions as the other way round. Here, Ill examine each of these contentions. This is an evolving document. Over time, Ill gradually flesh out the points and add interesting new contributions to the debate. I find the idea that indeterminism restores free will extremely unpersuasive. What difference does it make if my conscious choices were programmed in at the big bang or decided on the fly by random particle events? Also, at a deep level, quantum mechanics is not random at all. Schrödinger’s equation is completely deterministic and time-symmetric. Carroll feels much the same: Others, though, do see a role for indeterminism. Quantum gravity theorist and blogger Sabine Hossenfelder recently offered some thoughts. Her paper suggests that there is a third way between determinism and randomness: what she calls “free-will functions,” whose outputs are fully determined but unpredictable. Only those who know the function know what will happen. This is distinct from chaos, in which the function is universally known but the initial conditions are imperfectly known. My first reaction was that the free-will function is operationally the same as a classical deterministic hidden variable—namely, there is a deterministic description of a system, even if we can’t tell what it is. After viewing Hossenfelder, I think her point is that whereas hidden variables are part of the state of the system, the free-will function is part of the laws of nature. It is not a hidden variable, but a hidden law. Nature still meets the definition of determinism—a given state evolves in a definite way—even if the rules guiding evolution are unknowable. The free-will function might not be definable as an equation or algorithm, but would be what theoretical computer scientists call an oracle. Another connection to free will hinges on the phenomenon of entanglement. Does the spookily coordinated behavior of quantum particles reflect a nonlocal connection between them or, alternatively, some built-in cheat sheet that allows them to arrange their answers in advance? In the 1960s the Irish physicist John Bell devised an experiment to decide between these possibilities. For a visual metaphor to understand the phenomenon and dilemma. In philosophy, systems theory, science, and art, emergence is conceived as a process whereby larger entities, patterns, and regularities arise through interactions among smaller or simpler entities that themselves do not exhibit such properties. In philosophy, almost all accounts of emergence includes a form of irreducibility (either epistemic or ontological) to the lower levels. Also, emergence is central in theories of integrative levels and of complex systems. For instance, the phenomenon life as studied in biology is commonly perceived as an emergent property of interacting molecules as studied in chemistry, whose phenomena reflect interactions among elementary particles, modeled in particle physics, that at such higher mass—via substantial conglomeration—exhibit motion as modeled in gravitational physics. Neurobiological phenomena are often presumed to suffice as the underlying basis of psychological phenomena, whereby economic phenomena are in turn presumed to principally emerge.
Posted on: Sat, 23 Aug 2014 15:56:46 +0000
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