Quantum Gravity Expert Says "Philosophical Superficiality" Has Harmed Physics
blogs.scientificamerican.com
blogs.scientificamerican.com
I have studied computer science and got interested in physics and philosophy of science thanks to him, he kind of embodies my idea of science, and of civil responsibility, and I must say I have been a bit disappointed to see that also the academic world is full of "scientists" that underestimate the value of philosophy or other related subjects, or that teach students not to question "too much" what they are doing, preventing them to really see the "big picture" behind knowledge.
Krauss et al's statements on philosophy are simply that when you build a particle accelerator, walk into a lab, or start working out mathematical theories, you don't start with philosophy of science. That's a backwards rationalization of how science is done, constructing it's underpinnings/justification after the fact. Most scientists who conducted experiments and proposed hypotheses throughout history did not start by first making sure what they were doing aligned with the Philosophy of Science. And indeed, children conduct scientific investigations all the time blissfully unaware of the philosophical underpinnings justifying it.
I'll go one further and say that the idea that you never need to do "what if" theories, but merely explore the existing ones to their ends, can lead to local optima. It is certainly possible you will run into the limits of the conceptual underpinning of the theory in which no iterative refinement can fix it in a way that leads to superior understanding.
Philosophy is useful, in the same way that logic and mathematics are useful, to explore formal systems, especially when the real world experiments are impossible or unethical to conduct. But the limits of philosophy are also born out in the assumptions used -- e.g. arguments about free will or consciousness, debates are artificial definitions that do not measurably or provably reflect the real nature of real things.
Perhaps a better commentary here: http://whyevolutionistrue.wordpress.com/2014/08/23/accommoda...
1. On historical science. The process of science has changed drastically over the centuries. To discover the law of gravitation, a few people with telescopes had to tabulate a few thousand data points, do some manipulations and discover the law. For the search of the Higgs, eg. the statistical procedures to be used where established well in advance of data collection to avoid potential biases. The idea is that more advanced science requires more careful procedures and analysis. Rovelli is arguing that we need to change our method yet again towards being more careful and formal to make advances.
2. Your first paragraph is a strawman. There is much more to the philosophy of science than your examples. See [1]. Or consider that "what is probability?" does not have a good answer. This is a question that philosophy struggles with and that has deep relevance to physics - eg. the ontology of quantum mechanics.
[1] http://www.preposterousuniverse.com/blog/2014/02/24/post-deb...
What is the relevance? We're able to make accurate experimental predictions about probability already - theorising about "what is probability?" could just be meaningless speculation unconnected to reality, which is exactly his problem with String Theory. No?
I have read this awnser¹, and it certainly looks good. Perhaps even kind of obvious.
One cannot reasonably say that "what is a probability?" doesn't have a good answer without having read at least the first two chapters of "Probability Theory: the Logic of Science".
I don't want to enter a Frequentist/Bayesian debate, where I'm right and the Frequentists are insane. But the views presented on this book didn't really surprise or enlighten me¹. Instead, I was more like "of course, why the fuss?" Many of the claims in this book really did felt obvious.
"What is a probability?" does have a good answer. Anyone saying otherwise should probably look at it, and explain why it's not good. I personally don't expect strong counter-arguments. (And if one throws me the problem of priors again, I'll crush him under the sheer weight of the hidden priors we can find in Frequentist methods.)
[1] With one big exception: the consistency proofs. I didn't know we could derive Probability Theory from so few axioms.
Thus, for anything to be empirically real, it
must be spatial, temporal, and causal. Yet space,
time, and causality cannot be proven to be
empirically real themselves! If space is thought of
as an empirical entity, the insoluble problem arises
whether it is finite or infinite. In the first case,
there would have to be something 'outside' space, a
metaspace, which is an absurd notion; but in the
second case it could never be differentiated of
anything and would therefore have no identity. If
time is finite, there would have to be something
'before' and 'after' it, which again is absurd; but
if it is infinite, it would take an eternity to
arrive at the present moment, which therefore could
never come about. Finite causality would enhance an
unimaginable 'first cause' of all events in the
universe, while infinite causality poses, mutatis
mutandis, the same problem as infinite time.
Given that the very foundations of causal logic (cause --> event) assume our ability to differentiate in time and space, it does seem as if the most interesting aspects of physics are operating in areas where open-mindedness helps.Now, since it is written by Schopenhaur, I feel it is in order to say that same thing, but with more words.
>Thus, for anything to be empirically real, it must be spatial, temporal, and causal.
I disagree with this. Entanglement, while not causing a breakdown in causuality, doesn't really obey it either. I would still consider it very real.
>Yet space, time, and causality cannot be proven to be empirically real themselves!
Well ok, with you definition of "real" they may not be. So?
>In the first case, there would have to be something 'outside' space, a metaspace, which is an absurd notion;
Ok, first I disagree that there would have to be something outside. And second I disagree that that would be an absurd notion. And third I disagree that it really matters at all. A scientist would switch viewpoint depending on which would be most convinient for the task at hand. Same as people use a coordinate system based that makes a problem the easiest to solve.
>but in the second case it could never be differentiated of anything and would therefore have no identity.
I'm not really sure what he is saying here, but I note that I could differentiate a metaspace from an apple. I don't really see why the lack of an identity (whatever that means) would be a significant problem.
>If time is finite, there would have to be something 'before' and 'after' it,
Eh, just no.
>but if it is infinite, it would take an eternity to arrive at the present moment, which therefore could never come about.
This is a little bit tricky. There are two different notions of infinity we need to distinguish. The first is two points in time with an infinity distance between them. The second is a backwards infinite ray. Ordinary coordinate systems have the second kind of infinity and work just fine. This is the kind Schopenhaur is talking about. The first type of infinity is more uncommon, but there is nothing in principle saying we can't have that either.
>Finite causality would enhance an unimaginable 'first cause'
That says more about his imagination than the it does about the universe.
If you think this, you don't understand entanglement (which is understandable because the popular press does an abysmal job of explaining it, as do many physicists).
Entanglement and measurement are the same phenomenon. Measurement is nothing more than macroscopic entanglement. See:
Here we are having philosophical debates about it, but I suspect if we just stuck with the math -- regardless of our intuitions -- most of these kinds of arguments would turn out to be a distraction rather than a solution to the problem. That's kind of the point many empiricists like Krauss are trying to make.
I believe that it is not possible for an infinite amount of time to have elapsed before this moment in time. I think that is what the quote in question is attempting to state.
Scientists "freeze" light inside a crystal for one minute. [0]
Stopping single photons in one-dimensional circuit quantum electrodynamics systems [1]
[0] http://www.gizmag.com/stopping-light-inside-crystal/28610/
[1] http://www.ese.wustl.edu/~jushen/Papers/Stopping_Single_Phot...
In those experiments, "stop" usually means absorbed and later re-emitted.
This is not unique; I often feel this way when reading philosophy.
So I kind of understand where Hawking / Tyson / et al are coming from. I do think it is a mistake to single-handedly dismiss all of philosophy, and I agree with the sentiment in this article that physicists are following an implicit philosophy that they do not understand, so there's a contradiction there. At the same time, most philosophy is honestly pretty bad.
There is nothing naive about recognizing that human knowledge is limited by our knowing apparatus. What is truly naive is to mistake the models of science with "reality itself" (a nebulous term)
Perhaps a more valid way to phrase the same sentiment would be to say that science, because of its assumptions and methodologies, can only address phenomena that are spatial, temporal, and causal. There might be real things that have none of those attributes; science and philosophers would have difficulty studying them, but that difficulty does not rule out the possibility of their existence.
edit: spoken or written
"Yet space, time, and causality cannot be proven to be empirically real themselves". This is akin to mathematical axioms that escape proof within a formal system. Of course one can debate whether the analogy applies for space and time as it does in arithmetic, but this is beside the point. My point was that Schopenhauer's quote was not even remotely close to being naive, especially considering when it was said (i.e. years before Godel and others proved similar conclusions).
No it isn't. Unless you understand quantum gravity better than anyone else does, there is absolutely no connection whatsoever between the possible empirical reality of spacetime and causality, and Godel's description of mathematical incompleteness.
Spacetime is observable, not axiomatic. The whole point of theories like loop quantum gravity - and one of the main reasons that the string theories are poor relations - is that LQG theories take an explicit interest in possible mechanisms that explain the observed properties of spacetime and causality.
In the jargon, they are 'background independent.'
For example, take a look at Causal Dynamical Triangulation:
The naivete is that a sophisticated philosopher would understand this, and at the very least not push forward a philosophical argument that really hinges on connotations of words instead of logical/philosophical pillars.
Anyways if the statement didnt have a famous philosophers name attached to it i doubt it would have gotten any response, its a pretty baseline/naive reaction to a complex scientific idea.
Yet, realism is in a completely different level. You can not reason about it using mathematical constructs. (Too bad that's the only tool we have.)
You may be saying this has already been done elsewhere but without references u can't just throw this out there as a given.
To ask what's before beginning of time is akin to asking what is the point more southern point of earth than the Southern pole. Answer is there is none.
In a place where space doesn't exist you wouldn't notice it not existing. Probably because you wouldn't exist as well.
It's a pity to see this come out in some of Rovelli's statements in this interview, because the rest of it is so wonderfully measured and thoughtful.
Here is a startup analogy. One is having a dream about building google and writing a paper about it. How it might work, eg. 20% time, etc. The other is actually building google.
I don't know how to figure out quantum gravity. I don't even know how to do an experiment which could distinguish between different models of quantum gravity. But I do know there's plenty of other interesting stuff (much of which is actually useful) we don't know about physics at other scales which we can spend our time and money on.
This sentiment has a long and storied past.
http://patentlyo.com/patent/2011/01/tracing-the-quote-everyt...
> But I do know there's plenty of other interesting stuff (much of which is actually useful) we don't know about physics at other scales which we can spend our time and money on.
Yes, true, but the low-level stuff only describes. Theory formation attempts to explain. Explanations are required for science.
What do you imagine the current portion is? Most funding does go to experimental physics.
I think string theory as a theory of everything is an excellent example. From the outside at first it seemed promising, but nowadays looks more like a very complex mathematical chimera which we don't have a particular way of proving nor disproving. But string theorists insist that these aren't merely thought experiments, this is SCIENCE, even if we have to add dimensions and multiple universes we never experimentally detected to try to make it work. Maybe it works in a blackboard, ¿but how do we know it reflects reality?
Philosophy of Science should be useful to check if we are doing science right or are being carried away by beautiful math and thought experiments. Maybe a scientist doesn't need philosophy a priori to do science, as a doctor doesn't need philosophy to cure people, but both epistemology and ethics are useful to contemplate if we are doing it right or something should be improved. At least that's my opinion.
* Of course it's just Plato relating what he says are Socrates's arguments, so there's that too.
This struck me when the author, in his introduction, mentioned a previous Q&A with telepathy proponent Rupert Sheldrake. Sheldrake only gets a brief mention in this piece as a critic of science, and I hasten to add that I don't have any beef with the article from that point on.
For anyone who doesn't know, Sheldrake has for years been trying to convince people that telepathy is real. To this end, he's done a series of experiments which had the kind of inconclusive results you'd expect, yet in spite of a dearth of convincing, published results, in spite of a global failure to replicate his results, he keeps badgering science to take him seriously. Having been met with apathy and mild derision, he now blames science on his failure to be taken seriously.
So yes, Sheldrake is a "science critic." So are many of the purveyors of homeopathy, of miracle cancer cures, of coffee enemas, of dowsing and of Intelligent Design. Science is empirical, and people without evidence like to call this a shortcoming of science.
So my question is: how much debunking, how much finger pointing and pantsless emperors is required before we can in good conscience exclude certain groups of people from discussions about the philosophy of science? Those discussions are important, no doubt - and this is why I think we should be wary of allowing them to be bogged down by the contributions of frauds and crackpots.
Do you have a reference? The dog experiment seems statistically significant (http://www.sheldrake.org/research/animal-powers/a-dog-that-s..., shows ANOVA, F-value (df 2,22)=20.46; p<0.0001). ). What exactly about that experiment is inconclusive?
Note that I'm not saying telepathy exists. I'm discussing an experiment for which I have no sensible explanation. Is there some data/papers/methods I'm missing?
By the rules of the game, if he's not participating in this exercise he's not doing science.
If you look at the editorial board in http://www.scientificexploration.org/journal/ there are PhDs from a lot of prestigious institutions (Princeton, Sorbone, John Hopkins, Cornell) which of course is no warranty or rigor, but it may be an indication. The submission conditions show that the papers are peer-reviewed (http://www.scientificexploration.org/documents/instructions_...).
> I don't feel qualified to judge his setup or analysis
then we should suspend our judgement about the validity of the results, not discredit them by principle.
In this paper by one of those scientists http://www.richardwiseman.com/resources/psychicdogreply.pdf one of the scientists (Wiseman) reports that they were in fact not able to confirm Sheldrake's findings, that Sheldrake had criticized their criteria for measurement _after_ they had led to failure, and badgered them into arbitrarily establishing other criteria for success.
Wiseman also complains that he and his colleagues were badly misrepresented in Sheldrake's paper, and that Sheldrake tried to present excuses for the failed trials.
This post hoc selection of evaluation criteria is one way in which crackpots massage experimental data to substantiate their claims. Honest scientists usually do their best to avoid it.
In conclusion, in the one instance where an attempt was made to verify Sheldrake's strongest results, he was seen to be acting in a manner suspiciously characteristic of trying to introduce a bias in the direction he preferred.
Even if he isn't intentionally dishonest, this man is almost certainly a crackpot.
Lawrence Krauss: Philosophy used to be a field that had content, but then 'natural philosophy' became physics, and physics has only continued to make inroads. Every time there's a leap in physics, it encroaches on these areas that philosophers have carefully sequestered away to themselves, and so then you have this natural resentment on the part of philosophers.
Neil Tyson DeGrasse: Up until early 20th century philosophers had material contributions to make to the physical sciences. Pretty much after quantum mechanics, remember the philosopher is the would be scientist but without a laboratory, right? And so what happens is, the 1920s come in, we learn about the expanding universe in the same decade as we learn about quantum physics, each of which falls so far out of what you can deduce from your armchair that the whole community of philosophers that previously had added materially to the thinking of the physical scientists was rendered essentially obsolete, and that point, and I have yet to see a contribution — this will get me in trouble with all manner of philosophers — but call me later and correct me if you think I’ve missed somebody here. But, philosophy has basically parted ways from the frontier of the physical sciences, when there was a day when they were one and the same. Isaac Newton was a natural philosopher, the word physicist didn’t even exist in any important way back then. So, I’m disappointed because there is a lot of brainpower there, that might have otherwise contributed mightily, but today simply does not. It’s not that there can’t be other philosophical subjects, there is religious philosophy, and ethical philosophy, and political philosophy, plenty of stuff for the philosophers to do, but the frontier of the physical sciences does not appear to be among them.
I think what changed was physics became much harder to understand. Pre Einstein it was fairly easy for someone without much physics training to grasp Newtonian stuff. With the advent of general relativity and quantum mechanics it became hard to understand without years of study of physics which most philosophers do not have which led to their work being not very useful to the physicists. However philosophical insights by people who do understand the physics can be good in my opinion.
Feynman seemed good, for example. Simple stuff
http://lesswrong.com/lw/99c/transcript_richard_feynman_on_wh...
a bit more subtle, philosophical at the beginning:
http://www.feynmanlectures.caltech.edu/II_28.html
Feynman and philosophy:
https://philosophynow.org/issues/59/Richard_Feynman_Accident...
So true.
That's philosophy's territory, now that we have science. Philosophers don't have to, and feel no need to, reality-test their speculations. And I see I may be reflecting your views on this topic.
I would have liked to have more detail on his critique of the "guess and check" approach to science. My own opinion is that there is a very good reason why scientific progress follows the pattern he describes, of new theories being based on either new experiments, or in depth analysis of existing theories.
The reason is that science relies on belief in objective reality, and yet we don't know what objective reality is. So in order to reason about what the universe really is, the best and only starting point is our current model(s) of physics.
The moment we make an assumption about what reality is that isn't based in physical theory, we are liable to be wrong. For example, Newton was criticized for his theory of gravity, because people knew that reality was composed of little machine-like objects, interacting at a microscopic scale. There was no room in this worldview for Newton's "occult" force of gravity which acted at a distance.
Granted, there's a lot of material to cover, I don't think that's an appropriate response–especially when delivered with contempt, as it typically was.
"If GR means all the laws are related to the reference frame, does that mean all the things in it are relative too, like religion?"
"What if Dark matter really is more than just stuff that falls down. What if there are intelligent clouds there? What are their ethics like?"
"No but really, what is the definition of life?"
"Ok, so fetal stem cells, but what if we took a blood sem cell and then back tracked that into a fetal one. Is that wrong?"
All of these can take the 'Copenhagen Interpretation' given to undergrads. The Copenhagen Interpretation states: Shut up and calculate.
Philosophy of science is about as useful to scientists as ornithology is to birds
http://www.theguardian.com/world/2012/sep/06/vladimir-putin-...
If only some philosopher of science could lead the scientists the same way ( to the former USSR citizens - "poruchik, molchat!" :)