Submitted by BernardJOrtcutt t3_10df9ua in philosophy
Perrr333 t1_j4m1ura wrote
This was deemed too spicy for a regular post so it has been relegated to the weekly thread. As a result it is a bit too long, sorry 😬
Supertasks by VSauce
https://m.youtube.com/watch?v=ffUnNaQTfZE
This is a good video by VSauce on supertasks. Fun, informative, accurate; just watch it!
I'm posting this because I think it shines a light on an area of philosophy which I think is seriously flawed: metaphysics (downvotes incoming!). My problem with metaphysics is that it tries to reach conclusions about what exists which are too strong using "armchair" reasoning, when this should be better left to scientists, especially physicists. While philosophy does utilise cold hard logic sometimes, especially to construct paradoxes to establish what isn't true, it often also requires other approaches to arrive at conclusions about what is true, such as coming up with different theories which fit, valuing parsimony, etc. But when it comes to establishing what exists, it's the scientists who should be left to come up with theories that fit, utilise parsimony as they see fit, do experiments to narrow things down, etc., and yes they can also be trusted with the cold hard logic when it comes up. They get to decide when a question is more concretely answered vs. when there isn't sufficient information and so there are only hypotheses.
So how does this relate to Michael's video on Supertasks? Supertasks originated as thought experiments, specifically paradoxes, thought up by philosophers. The two most famous are Zeno's paradox and Thomson's lamp. Michael explains the correct answer to both, which was stated firmly by Paul Benacerraf back in 1962: all these supertask thought experiments ultimately come down to a lack of information (like one of those logic puzzles where one of the options is "not enough information"). So they aren't really paradoxes at all and don't tell us anything about reality.
That doesn't mean that these thought experiments are useless. They should be better thought of as puzzles, which tell us something about reasoning, and open interest into what physicists may one day discover, or what mathematics might apply. Often puzzles have been the foundation on which beautiful and interesting maths is built. Indeed, it feels like metaphysicians are often pulling interesting ideas which belong in maths or physics into their department, because while they aren't qualified to tackle them properly they still need to publish papers.
Now, for some philosophers like Alexander Pruss this isn't enough: they want to use these thought experiments to reach conclusions about what exists. In Pruss's book 'Infinity, Causation, and Paradox' (2018) he uses supertasks and other reasoning to try and argue for his position of causal finitism, which roughly implies that none of these paradoxes could ever come about in reality.
But this is just not necessary and an overreach of philosophy. Let's take the example of the green and yellow cube at timestamp 10:57 in the video. If a cube like this did exist in reality, yes it's true that the colouring algorithm does not tell us the colour of the top. But maybe physicians would find out that the top colour must always be green, or always yellow, or always a quantum superposition of the two. All answers fit because the supposed paradox isn't a paradox: the colouring algorithm doesn't give enough information to determine what the top colour is. So the thought experiment is interesting and opens up questions about reality, but can never answer them. Zeno's paradox is much the same: all it tells us it that physicists must determine how motion works; maybe because motion is continuous (so the limit of the partial sums gives the answer, as expected), maybe because space is not infinitely divisible, or something else.
I've only been talking about a small slice of metaphysics, but it is my personal opinion that this a microcosm which correctly shows the sub-discipline's flaws (I can feel the downvotes running through my veins ❄️). This is of course my personal opinion, and seeing as I'm posting it anonymously on Reddit it's worth pretty much nothing, but I thought I'd voice it here anyway to give a little balance to this subreddit.
If you actually read this far, well done! Here's a cake 🎂
el_miguel42 t1_j5c0377 wrote
As someone with a background in physics who every now and then browses this thread. I agree with you completely. My biggest gripe with metaphysics isnt the logical process. Its that for some unknown reasons philosophers in the realm seem to assume that observations made at their (macro) level apply to all scales and scenarios.
Perrr333 t1_j5c6fvm wrote
I read this laid back debate between Julian Baggini and Laurence Krauss a while back (https://amp.theguardian.com/science/2012/sep/09/science-philosophy-debate-julian-baggini-lawrence-krauss) where Baggini essentially concedes that metaphysics should be replaced by physics. At the time I wasn't really ready to make that concession, but know I see it differently. Other than that point the debate isn't great, with both participants mostly talking past each other, but that point always stuck with me.
Edit: I found it because at the time I was frustrated by so-called "scientism" which I was seeing everywhere, and was trying to find places where scientists had espoused it. I still think scientism is largely wrong and harmful, but I view it more sympatheticly. It's sad but ultimately unsurprising that physicists like Feynman subscribed to it. Only a few physicists like Sean Carroll are even willing to engage with philosophy. Which is annoying because while I don't care much for metaphysics, interpretations of quantum mechanics which imply nonsense like the moon isn't definitively there whilst you're not looking at it are just so nonsensical that I have to hope for theories like objective collapse to win out.
el_miguel42 t1_j5ck05l wrote
LOL! I know what you mean, ive seen some crazy explanations for quantum phenomena and some of them are pretty nuts. The issue isnt quantum mechanics, its the interpretations of it.
Essentially what physics has done is observe a bunch of stuff, and then see if its possible to get maths to fit the observations. In some cases the maths is elegant, in other cases its crazy and messy.
The issue is it seems to work. Here's the important part. We don't know Why it works, we just know it does. We know it does, because we have observed and tested it - loads, but the why of it eludes physicists. The reason why some of the explanations (quite a lot of them) appear nonsensical is because when you take the maths, and try and turn it into physical reality its just... weird. The problem is, unless your a physicist people want examples, they want a demonstration, an analogy, and there just isn't a very good one, because its so weird. As such you end up with this often talked about, but little understood topic. This is especially common when people talk about anything to do with superposition, collapsing a wavefunction, observers etc and leads to crazy analogies like disappearing moons and cats which are neither alive nor dead etc.
I will try and clarify most of this stuff in a small example. If I give you $5 and $10 and ask you for the total. You will answer $15. This is a mathematical expression to which you have a numeric answer.If I am about to roll a dice and ask you which number will it land on, in that scenario your answer will be "I dont know". Now you could absolutely give me a probability - you could say "its a 1/6 chance of landing on a number between 1-6". Essentially rather than give me a numerical answer, you have to give me a function as an answer, and as this function will give you a probability we call it a probability function.So there is no way to know which number the dice will land on, but you do know the probability function of the dice and you can tell me there's a 1/6 chance of it landing on any of its sides.So now we roll the dice, once its stopped rolling and we then look at the dice, you can now tell me the numbers its on! You no longer have a probability function anymore because you can now observe the actual value.
This is in essence what most of the misunderstanding of quantum physics is about. We have observed that the probability function of a lot of quantum events happens to be in the form of a wave. So while the quantum event is happening the prediction of its position, or momentum, or energy etc is a probability function. We dont know what the number is, but we know the likelihood of it being certain values. Then when we observe the event, its like looking at the dice after its finished rolling, now we have a specific value. In physics this is given the fancy sounding term of "wavefunction collapse".
So when you come across the nonsense descriptions they're normally trying to say that until you "measure" or "observe" the quantum object, it will be in a "superposition of states" and is in neither one state nor another. (essentially while the dice is rolling its value is not a 2 or a 4 yet, its a probability function). Once you measure or observe it, then the wavefunction collapses and then you can observe its state. (once the dice stops rolling you'll have an actual value rather than a probability)
Hence the cat is neither alive nor dead until you open the box, the moon isnt there until you observe it etc etc. Its just people taking the maths probability stuff in a literal sense and applying it to absurd examples.
Perrr333 t1_j5e62x5 wrote
Yeah. But it's also important not to stray too far into instrumentalism, the idea that none of the mathematics of physics needs to correspond to anything in physical reality, it's just an accurate prediction apparatus. Because the only reason a prediction apparatus can be consistently successful is if it is latching on to some elements of reality which follow constant, or at least very slowly changing, laws. There was a course I didn't have the time to attend covering the span of the history of physics from start to now, expounding the idea that while it has never been an entirely correct reflection of reality, it is an ever-evolving dialogue with reality. As we make new discoveries we refine our understanding of the world. Maybe at some point we will understand its true nature - maybe we already do, in the sense that there won't be any serious rewriting of the current mathematics, only the addition of new elements for e.g. new particles. There is a reality to the quantum realm as with everything else, and maybe one of the current interpretations will prove true, or maybe our dance with reality will give rise to new mathematics and new "interpretations". Because while physicists might call them interpretations due to the often sole dependence on the current mathematics, they are in fact hypotheses about the world, which ultimately have to prove true or false. We often forget that the theory of atoms used to just be an "interpretation" stemming from the mathematics of chemistry.
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