Vincenzo Manto

Title: What I believe about determinism, free will and faith
Author: Vincenzo Manto
Date:
Keywords: PhilosophyPhysics

What I believe about determinism, free will and faith

Abstract:

In the last few years, I always wanted to write down a way of thinking about physics, mind and faith that has taken shape for me over the past months. What follows is simply how I have chosen to fit existing ideas together and why.

What I believe about determinism, free will and faith

I wanted to share in the past years my thoughts regarding physics, mind and faith which have formed over the course of the past months. I would like to make it clear from the very beginning that none of the statements below are original to me. Thus, the following are just my interpretations of already existing notions and thoughts and the reasons behind that.

Physics that I believe in

The standard interpretation of quantum mechanics leads one to conclude that randomness is the basic principle of the universe. I do not entirely agree with that statement. It is possible to interpret quantum mechanics in such a manner that the universe has definite position of particles at all times. Nothing is collapsing anywhere. Wave function guides the particles according to a law which does not violate any other laws of nature. This is the de Broglie–Bohm (pilot-wave) theory.

This formulation makes identical predictions to the well-known and celebrated Copenhagen interpretation of quantum mechanics. No experiment has yet distinguished between the two and in fact, it seems by the nature of both theories that no experiment will ever be able to (see empirical equivalence discussion). The decision to use the Bohmian formulation rather than the Copenhagen interpretation is not one that is forced on you by physics. It is a personal preference for a description of reality where things exist independent of measurement.

If this is the case, then the universe is deterministic. Not in the sense that everything is predictable, for chaos theory prevents this from being possible, but in the sense that nothing is left to chance. The randomness we observe in quantum mechanics is merely the result of human ignorance of the initial state.

I wish to be clear that this is a matter of preference and not of science. Those whose judgment I respect prefer different descriptions and they are certainly not incorrect in doing so.

Implications for Freedom

This was the point at which I needed to adjust my thinking. There is an old idea, by a scientist called Donald MacKay, known as his “unpredictability of the mind” / logical indeterminacy argument, to the effect that a system that attempts to calculate its future in perfect detail ends up running into a paradox – in attempting to calculate the future it changes the future. Therefore a mind is incapable of having an advanced picture of all of its choices.

It is tempting to see in this some sort of true, uncaused freedom. But there is none of that. All that follows from it is the inability to perfectly predict my choices from the inside. It is an epistemological limit on self-knowledge, not evidence of uncaused choices. If the universe is indeed deterministic, as I am sure it is, my choices must have causes; they must have origins in my past, my personality, my motives.

The type of freedom that I could still claim would be a limited form of what philosophers call compatibilist freedom. Namely, my choices are free not because they happen to have no cause, but because they are my reasoned choices made of my own accord.

Popper, my epistemic love

My approach is heavily influenced by Karl Popper, but not strictly so. Popper believed that probability could be a physical property, or ‘propensity’, of the situation in question. However, as far as I understand now, it is not a viable theory. According to a philosopher Paul Humphreys, the notion leads to a contradiction — known as Humphreys’ paradox — the probability, or ‘propensity’, should be an attribute of the situation before its measurement, but the measurement is changing the very situation which was described by it.

What I find appealing in Popper is much more straightforward and robust: the truth is not given to us directly; we form hypotheses, we test them against reality and are corrected and try again. This is his falsificationism / critical rationalism, and what my concept of the mind consists of.

The limitations of any mind drawn from Goedel

Sometimes I think of Goedel’s incompleteness theorems, which formally state something quite technical about mathematical systems, but let myself draw from it metaphorically and say that no finite mind – mine included – can possibly grasp an absolutely comprehensive and perfectly verified understanding of itself and its world simultaneously. I want to be clear that this is a metaphor, not an actual theorem regarding minds — for a caution against over-extending Gödel this way, see Franzén’s Gödel’s Theorem: An Incomplete Guide to Its Use and Abuse — but simply something I believe to be true.

Where I place my faith

Everything I have said thus far I am willing to stand behind as a coherent and valid point of view, one among many. What follows is not the same. I am not going to try to say that physics leads there.

First, I am a Christian and I think that the image presented above, a universe with order and intelligence instead of chaos and structure, is an echo of the beginning of the gospel of John, Logos, which translates as the Word, or order, lying behind everything. Again, this is not a scientific fact that is being proven by physics. A physicist can agree with everything I said about Bohmian mechanics and determinism without feeling anything religious at all and this would be a perfectly legitimate stance.

Incompleteness is another example of the same kind. I personally think of the Incarnation as a solution to the impossibility of the self-completion of any finite system. Again, this is the way I resonate with the physical picture and not a logically necessary conclusion.

And likewise how I try to treat others. For if the universe is one single interconnected whole, as Bohm’s notion of “undivided wholeness” implies, it seems natural to interpret this in terms of the traditional injunction to love my neighbor and to recognize the other as somehow interconnected with me and not as an outsider. And this, again, is the way that I choose to see things, not the way that physics demands that I see things.

What it really is

It is an arrangement of existing elements and a particular interpretation of quantum mechanics, a properly corrected Popperianism, a plausible conception of freedom of the will, a figure borrowed from Goedel and my own personal belief system. The only possible original element of mine, if there is any at all, would be simply the form of the combination itself and the willingness to admit where the reasoning ends and the choosing begins.

I’d like to call it a compatibilistic and rational belief based on the growing and bounded knowledge of humans.

References