The Duck Test

Sabine Hossenfelder is best known for her popular youtube physics channel, which has over half a million subscribers. She is noted for being strongly opinionated on questions of physics and cosmology, which adds to the appeal of her channel. She regards a lot of speculative hypotheses by other physicists to be ascientific since they are not provable or disprovable even in principle. Many are just “modern creation myths written in the language of mathematics.” Regarding the multiverse she says “such copies are both unobservable and unnecessary to explain what we can observe.” This is not to say the idea is wrong, she adds, just that it has more in common with faith than science.
 
In her book Existential Physics on metaphysics it is no surprise that her style is much the same. It’s an interesting book although, strangely, not much help with the existential questions it addresses, since mostly she writes about the limits of science rather than what science reveals. Her anecdotes of discussions with other physicists (she is not the least bit intimidated by Nobel Prizes) are by themselves worth the read however. She does take a firm stand on a few things. To the question of whether the past still exists in some sense for example she answers yes. Since special relativity tells us that observers in different reference frames cannot agree on a “now” moment, then past, present, and future are just coordinates – your present can be someone else’s past and both moments are equally real. She has no patience for free will regardless of whether the universe is ultimately deterministic or probabilistic: “according to the currently established laws of nature, the future is determined by the past, except for occasional quantum events that we cannot influence.” (As did Einstein, she suspects the universe is deterministic by the way – that the probabilistic nature of quantum physics means the theory is incomplete – but merely suspects it rather than believes it.) All in all, Existential Physics is a good read though I recommend first sampling some of her videos to get a sense of who she is.

 
I do have a comment on free will however. Whether it “really” exists or not has been debated by greater minds than mine for literally thousands of years. I’m not the one who will craft the definitive answer. A surprising number of physicists are compatibilists, to the annoyance of Hossenfelder, but I’m not going to debate the merits of compatibilism either. I’m simply going to argue that it doesn’t matter.
 
I’m a fan of the simple Duck Test. (Walter Reuther, President of the United Auto Workers 1946-70: “If it looks like a duck, walks like a duck, and quacks like a duck, it probably is a duck.") As a practical matter, free will is a duck. It feels like we have it and as a pragmatic matter we do. We not only can make choices, we cannot avoid making them since refusal to choose is a choice, too. Making choices is a condition of existence. This is the whole point of existentialism: humans are terrifyingly inescapably free. (Sometimes all of our available options are bad ones in terms of consequences, but they are still options.) We do not escape moral responsibility for our actions by saying, “Hey, it’s not my fault: my actions were baked into the structure of the universe from the moment of the big bang.” No oppressor (who after all is just as much under the whip of fate as the oppressed), no thief, no cheat could be held accountable by that argument. Liberation movements would be meaningless. Liberation to what? The dead hand of fate?
 
As a practical matter our wills are free, and we will not thrive if we behave otherwise. We cherish our freedom of choice with good reason. But is there some sense in which this freedom is an illusion? At some subatomic level is the fix in (as hard determinists would say) or are events purely random (as the probabilists would say)? Maybe. Perhaps even probably. But we don’t live at the subatomic scale. We live up here. Up here, it doesn’t matter. We make our choices and we live with them.
 

Cold Blood (Lydia Pense) – 

I Wish I Knew How It Would Feel To Be Free