joigus

I sympathise with your position, for many years it's been my own position, but influential scientists like Lawrence Krauss insist on claiming the concept of the physical vacuum as a substitute for "nothing" (A Universe from Nothing), so (for better or worse) it has permeated to the general culture. And you need to take that into account if you want to dispel some confusion in people who strive to understand these concepts.

This is very much along the lines of what I wanted to say. How can you cut "nothing" in disjoint pieces and tell them apart, keeping track of the one that's inside your box and the one that's outside? Some questions make no sense. And what's more; some concepts (even with no predicate) make no sense. Examples: The position of unanimity The sympathy of the rock etc. If you want to make sense of an idea of "nothing", you need to go back to physics. And the salient idea from physics that's closest to "nothing" is the vacuum. And the physical idea of the vacuum looks nothing like that naive no-thing. For starters, it looks more like the box is sitting on the vacuum (it gets its mass from it, through the Higgs mechanism), rather than that the vacuum is a substance that can be trapped in the box. It also changes through cosmological evolution, it expands, etc. It's seamless, pretty much featureless, but not completely devoid of attributes. Science edits some of our ages-old philosophical ideas and completely revamps them.

Very interested in the answer to this question.

I'm not following your analogy here. Are the monkeys individuals, or genetic sequences, or the background chemical processes, in the analogy? Either way: How does the monkey "tell the other monkeys" once that particular sequence works, that it does and they must use it? I think we agree in most everything else and that we have established that evolution is not random. Yes it's true that most phenotypes are multifactorial. A well-known example is size. But when stochastic variables depend on many other independent stochastic variables the central-limit theorem guarantees that they will conform to a Gaussian. Something that in the case of size seems to be satisfied very well. This is a question about what particular probability distribution does the phenotype fit; not really about whether the selection process is random or not. The key question in evolution is that the throwing of the dice is one of a very quick step-by-step change (genetics) against a much, much slower erratic change (climate, competitors, etc.). And I think we all basically agree that the monkey model doesn't fit the bill.

This connects very much with point 3) by @Arete. Point 3), I think, is essential. Point 1) I don't think it's crucial as, in Eukaryotes at least, there's a considerable amount of DNA that's just got rid of by RNA splicing. So in eukaryotes there's a lot of RNA material that goes in the dumpster right away during the phase of transcription. I think what Arete's point is that Nature is much less forgiving to "mistyping" DNA than the monkey theorem suggests. Monkeys that mistype too much are removed (see below). Point 2) give the monkeys a chance to make some typing mistakes, as different codons give rise to same protein. Proofreading processes give the monkeys another shot too. This is equivalent to letting the monkeys disregard certain typographic rules, e.g.: ignore capitals, spell words phonetically, etc. We don't have infinitely many monkeys in our typing bench! "Random" by itself doesn't mean much. When people use the word "random" in such a way, they usually mean something like equal probability for all outcomes. Equal probability is not what governs evolution. Some changes are more likely than others. It's as if, for some reason, the monkeys are more likely to type the sequence "ow" than the sequence "wt". It is also known that some sequences of nucleotides are more prone to mutation than others. Trying to elaborate on @Arete's point 3), while connecting with the OP's analogy of the typing monkeys; it is as if every now and then, when a monkey makes a typing mistake that's too bad to be forgiven, some directing process kicks him off the team of typing monkeys and lets other monkeys take his job. So, again, it's not random. The environment has the final call on which monkeys keep typing an which don't. And internal processes determine which typing mistakes are immaterial, and which aren't.

As @exchemist says, evolution is not random. That's a misrepresentation commonly used by creationists to caricature the mechanism of evolution. If you think deeply about it, everything is random. The key for some kind of adaptation is that: 1) The replicating mechanism is fast 2) The background conditions, though being ultimately random, reshuffle so slowly as compared to the replication process as to provide a sufficiently slow background (and thereby effectively non-random) for the replication mechanism to adapt to them. Almost x-posted with @StringJunky and @studiot and I have to read more carefully the whole thread. X-posted with @Ghideon.

I still don't know what @dimreepr's position on the matter of Sharia in countries which already have a body of law really is. For example: That may be true, but I fail to see any direct connection to the topic of Sharia in the US.

LOL. Got it! What campus is that?

Who? Sorry, I'm lost. 🥴

Sorry. It may have been me who started the language issues. The sentence that, under Sharia, women can be free, left me worried. Then I agree that the thread was diverted into language too heavily. I don't particularly adhere to the fact that the forum is resurrected based on minor linguistic points, and only that. But I do insist that either you are free, or you aren't. Sometimes I point out a language item because it worries me that it hides something or tries to make up for something. In this case, if I said to you: "Don't worry, you can be free any time you want", you would be right to suspect it might reveal an important constriction to your freedom. The fact that "can" is used as diminishing the condition of free, to me, is not to be ignored. And the fact that a person who's presumably receiving instruction on Sharia feels compelled to say that women can be free under Sharia, to me, means something. Why doesn't the OP just say "women are free under Sharia"? See my point? Unfortunately neither the OP, nor anybody else has clarified this point. And I didn't insist on it, as I noticed that it didn't gather much attention.

By those who understand. That's why we say "I understand", and never "I'm understanding". But we always say "I'm learning".

It may take many setbacks to learn a lesson. Understanding, on the other hand, is instantaneous...

It's a matter of terminology, but I don't think "curse of knowledge" is off the mark. The first time you learn something, it's probably more accurate to call it understanding. But not every time the question pops up again do you reproduce the "understanding" part of it. You retrieve the data from your memory, because your really understood it long ago. You may even remember a reasoning, but it's just because memory is playing a role there that the key ideas for that reasoning can be conjured up almost instantly. You may be under the illusion that you're reasoning again, but you're drawing from your memory more heavily than you would like to believe. It happens to all of us, and it's to do with how the hippocampus works.

The motivations, historical background, technologies, etc in the 100-Years War, WWII, the Cold War, etc. are very different. I think we are losing focus; or rather, creating different focuses. One thing is for sure though: @Hans de Vries can rest assured there are many people here willing to discuss war besides him.

If M is "moles", that may be it. Then the number of moles of Cl would have to add up to .6 and the \(V_1\) and \(V_2\) that I mentioned don't enter into it. "M" generally represents moles per liter though... I hate trying to guess what they're asking. 😆 I hesitate to say that must be it.

Thanks @swansont. It should have been obvious to me, but the lack of "M" after 0.4 plus the typo really confused me. The only way I can make sense of this is that both are molarities, as @hypervalent_iodine says, and you have to solve for the respective number of moles, but also for the volumes of both solutions, that must add up to 1 L. The way I see it, the problem is underdetermined, as @studiot suggests, as you would have 4 unknowns and only 3 equations: \[\frac{n_{1}}{V_{1}}=0.4\] \[\frac{n_{2}}{V_{2}}=0.2\] \[V_{1}+V_{2}=1\]

I'm confused by "pf". I didn't know "pf" (as a unit of concentration).

I'm no expert but I'm always willing to learn. And it's related to science and engineering very directly. For example: -Espionage and the like from Julius Caesar to the Cold War (cryptography) -The paradox of the two generals or the coordinated attack (logic) -Alloys and other materials from the Stone Age to the Bronze Age to Magnesium alloys (materials science) And then, computers, ballistics, chemical warfare, biological warfare, cartography, the MAD strategy during the Cold War. Some of them very unnerving topics, but very interesting nonetheless. There are very knowledgeable people here, and I think those would be very interesting discussions.

I'm far ahead of you. It's much more elegant to write Einstein's equations in terms of upsilon: \[ \Upsilon=\frac{\tau}{3} = \frac{2}{3}\pi \] Gravitation would suggest a banana peel. And don't forget 2/3 is the charge of the up, charm, and top quarks. What can be more elegant than unifying bananas and quarks with gravitation?

In the classical theory it doesn't make sense to talk about "this" EM entity (a piece of field) and "the other" (another piece of field). All EM fields coming from all the sources in the universe contribute to one value of the EM field at this or that point. Quantum fields, on the contrary, allow for the possibility of several (curiously enough indistinguishable) quanta being tangled up with each other. And on top of that, everywhere in space. Quantum fields have this thing that you can count (a counting number). And entanglement occurs in this counting number. When EM fields are in the classical regime, there are so many quanta that this number becomes completely irrelevant and the field behaves like this entity that is built from all the EM fields coming from all sources in the universe. The classical field is roughly equivalent to the average number of photons in the quantum field. As to so-called non-locality, it's not a matter of anything travelling anywhere at any speed; it's rather a matter of a 2-quanta state being more like "one thing with counting number two" than like "two things" so to speak; so that changes in one part of the whole system being reflected in the state of both. It's hard to say in words, and we need the maths really. This "both" is not one and the other, as they are indistinguishable. Throughout the years, whenever I have been pressed to explain, I've contrived my own way of saying it so people kinda come to terms with it --if not totally understand the same way we understand, e.g. a rock falling. Nobody does, and I for one don't. The way I say it is: "particles are instanciations of a field". And I've even borrowed the verb "instanciate", which I think programmers use on a daily basis. These instanciations are tangled up. You can't say which one is which. There is no "which". And nothing is travelling from one to the other, as there is no "one" and "the other". All quantum correlations are initial. They're there from the very preparation of the experiment.

Somehow I didn't felt the need to be blunt here. At times just quoting the other is enough.

I think the premise, "nothing happens, something happens, or something else happens" is extremely vague, and far too inclusive to be meaningful. The story with physics as just prediction/discovery or prediction/refutation is far too simple, as others have pointed out. Accidental discoveries, imagination, and other elements, like precision tests, play a role. Sometimes there are even uncomfortable compromises one must reach. On the theoretical side, most of the time it's about parametrizing the world, and then mapping it with those parameters. You could say that physics is more akin to cartography. A very sophisticated cartography. On the other hand, physics is not under the same strictures as mathematics. Obtaining a theory that's a mathematical delight would be wonderful, but it's not the main drive of most physicists, I think. I think most physicists have come to terms with the fact that good physical theories don't have to be logically complete. Good physical theories are not as directly affected by mathematical necessities either. I'll give you an example: Whether Planck's constant is a rational or an irrational number is not only uninteresting, but completely meaningless from the physical point of view.

Total energy: \[E=\frac{mc^{2}}{\sqrt{1-v^{2}/c^{2}}}\] Rest energy: \[E_{0}=mc^{2}\] Kinetic energy: \[\textrm{K.E.}=\frac{mc^{2}}{\sqrt{1-v^{2}/c^{2}}}-mc^{2}\]

Just to clarify --although Swansont and Ghideon are doing a very good job of it--. For a particle of mass m --mass is just rest energy: Total energy: E=mc21−v2/c2−−−−−−−−√ Rest energy: E0=mc2 Kinetic energy: K.E.=mc21−v2/c2−−−−−−−−√−mc2 Rest energy is akin to positive potential energy. These concepts were clarified in Taylor & Wheeler Space-Time Physics a long time ago. Mass is better understood as rest energy.

Can you reproduce any piece of known physics with your theory? Let's say Coulomb's law, or Newton's law of gravity, or the like.