joigus

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.

... for visible light.

Exactly as @exchemist says. It's not that if you shoot very energetic photons against hydrogen atoms the photoelectric effect doesn't go on. It does. But the clever trick is to use a metal, because there you can show that no matter how many photons you shoot against the metal, they won't free electrons from the metal unless they have the required frequency (energy = h x frequency). They would just be absorbed by the continuum spectrum (available energies) of the metal. And that threshold energy is nicely shown in a metal because there is a sharp gap of energy that the electrons have to surmount if the are to be kicked off from the metal. So the metal: 1) Completely absorbs any photons below the threshold kick-off energy 2) Emits electrons when the frequency surpasses that threshold energy They act like a very efficient switch for the photoelectric effect.

The result of the integral doesn't depend on which approximation you use. The second one is called the lower Riemann sum. There is another one with starts with what you would call \(f\left(x_{0}+\triangle x\right)\) instead of \(f\left(x_{0}\right)\), and ends with \(f\left(x_{1}\right)\) instead of \(f\left(x_{1}-\triangle x\right)\) It's called the upper Riemann sum. Your expression differs only in a second-order term in \(\triangle x\). You only see a big difference because your \(\triangle x\) is enormous in the image. You can actually do an even better fit by taking a polygonal approach to the curve (for the same step \(\triangle x\).) https://www.geogebra.org/t/upper-and-lower-sum?lang=en Sorry. This is the applet that I meant to show you. You must play with the n=10. Take it up to n=24, for example, and you'll see what I mean. https://www.geogebra.org/m/SNS8SYSg

I think you're only too obviously an LTP. And I'm too busy to play LT now. I'm expecting a visit from HWL.

You mean in the literal sense? We can play this game forever.