- Hegel. I haven't found any resource that can explain it clearly.
Ask HN: What scientific phenomenon do you wish someone would explain better?
441–450 of 839 posts
Re: Ask HN: What scientific phenomenon do you wish someone would explain better?
#442Quantum Computers. Not like I'm five, but like I'm a software engineer who has a pretty decent understanding of how a classical turing machine works. I can't tell you how many times I've heard someone say "qubits are like bits except they don't have to be just 1 or 0" without providing any coherent explanation of how that's useful. I've also heard that they can try every possible solution to a problem. What I don't u…
If you understand Turing Machines, you probably also understand other automata. So you probably understand nondeterministic automata [1].
A quantum computer is like a very restricted nondeterministic automaton, except that the "do several things a once" is implemented in physics. That means just like a NFA can be exponential faster than a DFA, a QC can be exponential faster than a normal computer. But the restriction on QCs makes that a lot harder to do, and so far it only works for some algorithms.
As to why quantum physics allows some kind of nondeterminism: If you look at particles as waves, instead of a single location you get a probability function that tells you "where the particle is". So a particule can be "in several places at once". In the same way a qbit can have "several states at once".
> What I don't understand is how a programmer is supposed to determine the correct solution when their computer is out in some crazy multiverse.
Because one way to explain quantum physics is to say that the waveform can "collapse" [2] and produce a single result, as least as far as the observers are concerned. There are other interpretations of this effect, and this effect is what makes quantum physics counterintuitive and hard to understand.
[1] https://en.wikipedia.org/wiki/Nondeterministic_finite_automa...
Re: Ask HN: What scientific phenomenon do you wish someone would explain better?
#443I don't know if this would be my "one question" if I could ask the most brilliant minds in science, but something that always bothered me: When I took physics they basically said "at first scientists were disturbed by the fact that magnets imply that two objects are interacting without any physical contact, but then Faraday came along and said 'the magnets are actually connected by invisible magnetic field lines' and…
Maxwell picked up this idea and ran with it, developing a mathematical theory for the dynamics of the electromagnetic field. Instead of one object somehow magically interacting at a distance, interactions between objects resulted from changes in the electromagnetic field that propagated through space.
The final paragraphs of Maxwell's "Treatise on Electricity and Magnetism" are somewhat relevant.
This is 30-40 years after Faraday first wrote about lines of force, and there still wasn't really consensus about how to explain electromagnetic phenomena.
[emphasis added by me]
> Chapter XXII: Theories of Action at a Distance
> ...
> There appears to be in the minds of these eminent men, some prejudice, or a priori objection, against the hypothesis of a medium in which the phenomena of radiation of light and heat, and the electric actions at a distance take place. It is true that at one time those who speculated as to the causes of physical phenomena, were in the habit of accounting for each kind of action at a distance by means of a special aethereal fluid, whose function and property it was to produce these actions. They filled all space three and four times over with aethers of different kinds, the properties of which were invented merely to 'save appearances,' so that more rational enquirers were willing rather to accept not only Newton's definite law of attraction at a distance, but even the dogma of Cotes, that action at a distance is one of the primary properties of matter, and that no explanation can be more intelligible than this fact. Hence the undulatory theory of light has met with much opposition, directed not against its failure to explain the phenomena, but against its assumption of the existence of a medium in which light is propagated.
> We have seen that the mathematical expressions for electrodynamic action led, in the mind of Gauss, to the conviction that a theory of the propagation of electric action would be found to be the very key-stone of electrodynamics. Now we are unable to conceive of propagation in time, except either as the flight of a material substance through space, or as the propagation of a condition of motion or stress in a medium already existing in space.
> Hence all these theories lead to the conception of a medium in which the propagation takes place, and if we admit this medium as a hypothesis, I think it ought to occupy a prominent place in our investigations, and that we ought to endeavour to construct a mental representation of all the details of its actions, and this has been my constant aim in this treatise.
Re: Ask HN: What scientific phenomenon do you wish someone would explain better?
#444Crypto and practical security. I get tired of the circular “don’t roll your own crypto unless you’re qualified”. How does one become qualified? I don’t feel like I know how to evaluate many of the arguments people make for or against technologies people argue about on HN, such as Signal or different password managers. I feel like “security through obscurity” is a bad thing, and “layers of security” are a good thing,…
Edit: I should add that even if you are an expert in cryptanalysis, you still shouldn’t just roll your own crypto. It’s the analysis of the entire community, not the credentials of the author, that makes modern cryptography so strong.
Re: Ask HN: What scientific phenomenon do you wish someone would explain better?
#445What's the point of defining summation methods for divergent series? Do they have any connections to any other area of mathematics or physics? Is analytic continuation of complex analysis relevant to these things? How about p-adics?
I've started but haven't finished the physics lectures by Card Bender on mathematical physics, where he features perturbation theory prominently [2].
If someone could chime in on this, I would also be appreciative. Also if someone has better resources to learn about perturbation theory, I would also be appreciative.
Re: Ask HN: What scientific phenomenon do you wish someone would explain better?
#446Also are these charges responsible for some weather effects such as the jet stream. In a tornado is the negative charges on the dry side of the dry line interacting with the moist air on the wet side really just a local intense acceleration of the dry air trying to "get to" the oppositely charged moist air?
Are the rotation of low and high pressure systems basically due to the same condition? Is lightning also just basically a flood situation of the charges?
Re: Ask HN: What scientific phenomenon do you wish someone would explain better?
#447Re: Ask HN: What scientific phenomenon do you wish someone would explain better?
#448Re: Ask HN: What scientific phenomenon do you wish someone would explain better?
#449Crypto and practical security. I get tired of the circular “don’t roll your own crypto unless you’re qualified”. How does one become qualified? I don’t feel like I know how to evaluate many of the arguments people make for or against technologies people argue about on HN, such as Signal or different password managers. I feel like “security through obscurity” is a bad thing, and “layers of security” are a good thing,…
More generally, security is like any other field. You have to evaluate arguments based on the logic and evidence given. The main difference is that with crypto, it is much easier to shoot yourself in the foot and have catastrophic failure, since you have to be perfect and the attackers just have to be right once to totally own you. Thus the industry has standardized on a few solutions that have been checked really really well.
More generally, if you are interested, i would say read the actual papers. The papers on bcrypt, argon2 etc explain what problems they are trying to solve, usually by contrasting with previous solutions that have failed in some fashion. That doesn't mean reading the paper will explain everything or make you an expert or qualify you to roll your own crypto. Nor should you believe just because a paper author says something is a good idea that it actually is. It will however explain why slow hash function like bcrypt/argon2/scrypt were created and are better choices than the previous solutions in the domain like md5.
Re: Ask HN: What scientific phenomenon do you wish someone would explain better?
#450Sort of meta, but I always shudder when someone says that science has "proven" something. What sets science apart from most other methods of seeking answers is its focus on disproof . Your goal as a scientist is to devise experiments that can disprove a claim about the natural world. This misconception rears its head most prominently in discussions at the intersection between science and public policy. Climate change…
Not to be rude, but given current daily attacks on science and the scientific method, I can't let this stand - I think your meta intuition represents a fundamental misunderstanding of how science works. It is simply wrong to think that scientific questions can never be definitively settled. Clearly there are some hypotheses that have been difficult (and may be impossible) to prove, for example, Darwin's idea that nat…
It sounds to me like the grandparent is 100% correct.
> It is simply wrong to think that scientific questions can never be definitively settled.
They made no such claim, speaking of intuition.
> Clearly there are some hypotheses that have been difficult (and may be impossible) to prove, for example, Darwin's idea that natural selection is the basis of evolution
I've seen very little evidence in online discussions (Reddit for example) among armchair scientists that the theory of evolution is anything short of cold, hard, scientific fact.
> In the case of climate change, the problem again is that the evidence is correlative and not causal. Demonstrating a causal link between human behavior or CO2 levels and climate change (the gold standard for "proof") is technically challenging, so we are forced to rely on correlations, which is the next best thing. But, you are right, it is not "proof".
Is this (it is not proven) the message they're sending when they say things like "The science is in", just as one example?
> Establishing causality can be difficult but not impossible - the standard is "necessary and sufficient". You must show necessity: CO2 increase (for example) is necessary for global warming; if CO2 remains constant, no matter what else happens to the system global temperatures remain constant. And you must also demonstrate sufficiency: temperatures will increase if you increase CO2 while holding everything else constant. Those are experiments that can't be done. As a result, we are forced to rely on correlation - the historical correlation between CO2 and temperature change is compelling evidence that CO2 increases cause global warming, but it is not proof. It then becomes a statistical argument, giving room for some to argue the question remains "unsettled".
This is not the message I've heard, at all, from any mainstream news source, and it's certainly not the understanding of 95% of "right minded" people I've ever encountered.
> While some of the issues you bring are remain unproven, what's really absurd is to think that no scientific questions can be settled.
What's even more absurd, to me, is how you managed to find a way to interpret his text in that manner. And you're obviously (based on what you've written here), a genuinely intelligent person. Now, imagine how the average person consumes and processes the endless stream of almost pure propaganda, from both "sides" on this topic and many others.
The unnecessarily dishonest manner in which the government and media have chosen to represent (frame) reality to the general public has left an absolutely massive number of easily exploitable attack vectors for "conspiracy theorists" to exploit. And if you are of the opinion that all conspiracy theorists are idiots so you have nothing to worry about, consider the possibility that this too has been similarly misrepresented to you.
If a society chooses to largely abandon things like logic and epistemology in the education of its citizens, thinking propaganda is a suitable replacement, don't be surprised when things don't work out in your favor. If we can barely manage such things here, why should we expect Joe and Jane six-pack to somehow pull it off?