1 00:00:00,000 --> 00:00:12,720 Can you inform us about the four fundamental forces of the universe and the balance between 2 00:00:12,720 --> 00:00:13,720 them? 3 00:00:13,720 --> 00:00:17,880 Who possesses the faculty and knowledge that gives rise to these forces? 4 00:00:17,880 --> 00:00:25,100 Yeah, so the four fundamental forces has been really, I would say, a story of progress 5 00:00:25,100 --> 00:00:27,700 of unifying different things together. 6 00:00:27,700 --> 00:00:34,100 So we typically talk about gravity as one of these forces, about the electromagnetic, 7 00:00:34,100 --> 00:00:39,400 which is magnetism and electricity, and then two nuclear forces, the weak and the strong 8 00:00:39,400 --> 00:00:41,300 force. 9 00:00:41,300 --> 00:00:44,140 And so actually, that's been a story of unification. 10 00:00:44,140 --> 00:00:49,520 So it used to be that magnetic and electric forces used to be viewed as completely separate. 11 00:00:49,520 --> 00:00:54,420 And then with Maxwell's equations in the 1800s, those two were unified into one, which was 12 00:00:54,420 --> 00:00:58,080 what we call the electromagnetic force. 13 00:00:58,080 --> 00:01:02,880 Then later on in the 20th century, the weak nuclear force was unified in with the electromagnetic 14 00:01:02,880 --> 00:01:03,940 force. 15 00:01:03,940 --> 00:01:06,140 And so people would talk about the electroweak force. 16 00:01:06,140 --> 00:01:08,920 And so then we were down to three. 17 00:01:08,920 --> 00:01:14,640 And then now with the standard model, which we talked about before, the strong force and 18 00:01:14,640 --> 00:01:18,300 the electromagnetic and the weak forces are now unified. 19 00:01:18,300 --> 00:01:24,260 So in some ways, you could talk about two forces, the standard model and then the gravity 20 00:01:24,260 --> 00:01:26,880 as being the one which is left out. 21 00:01:26,880 --> 00:01:30,880 And it's not at all clear how to bring gravity into that picture. 22 00:01:30,880 --> 00:01:35,880 But one of the things I would say that has bothered people about the standard model is, 23 00:01:35,880 --> 00:01:43,460 again, this presence of tuning parameters, parameters that are not required by the theory, 24 00:01:43,460 --> 00:01:47,620 but have to be just right to match what the experiments are. 25 00:01:47,620 --> 00:01:51,600 And so this gets back to the aesthetic issues of physics. 26 00:01:51,600 --> 00:01:56,260 So initially, if you think about history going way back, we had five elements, you know, air, 27 00:01:56,260 --> 00:01:59,520 fire, water, and so on, it seemed very simple. 28 00:01:59,520 --> 00:02:03,840 Once people started doing chemistry, they found more and more elements. 29 00:02:03,840 --> 00:02:07,800 And so, you know, there's gold and lead and so on. 30 00:02:07,800 --> 00:02:13,340 And eventually, by the end of the 1800s, we had a hundred or more elements. 31 00:02:13,340 --> 00:02:16,620 And that just seemed too many for people, like why should there be so many elements? 32 00:02:16,620 --> 00:02:21,000 And so they started to seek for a way to unify those things. 33 00:02:21,000 --> 00:02:26,220 And lo and behold, they came up with nuclear theory, which then has looked simple at first, 34 00:02:26,220 --> 00:02:29,900 just protons, electrons, and neutrons, just three types of particles. 35 00:02:29,900 --> 00:02:32,040 And that seemed very nice. 36 00:02:32,040 --> 00:02:36,000 And then they continued to do nuclear physics, and they found, well, actually, 37 00:02:36,000 --> 00:02:41,040 now there are hundreds of types of nuclear particles, not just three, neutrinos, 38 00:02:41,040 --> 00:02:43,720 kaons, pions, and so on. 39 00:02:43,720 --> 00:02:45,280 And once again, it looked ugly. 40 00:02:45,280 --> 00:02:53,960 Like three somehow is appealing, but, you know, 246 seems not aesthetically appealing. 41 00:02:53,960 --> 00:03:02,960 So once again, they found a way to unify these into the standard model and quarks and gluons. 42 00:03:02,960 --> 00:03:07,200 And so, at first, there was a feeling that this would be very simple, that we would just 43 00:03:07,200 --> 00:03:12,960 have three colors of matter and we'd unify everything again. 44 00:03:12,960 --> 00:03:17,960 But once again, now the standard model, now we have something like 17 types of particles, 45 00:03:17,960 --> 00:03:21,960 each with different coupling constants and forces between them. 46 00:03:21,960 --> 00:03:23,960 And for many people, it looks like too many. 47 00:03:23,960 --> 00:03:25,960 It doesn't look pretty. 48 00:03:25,960 --> 00:03:31,960 At every stage along the way, what you see is we have tuning parameters, things that are, seem 49 00:03:31,960 --> 00:03:33,960 to be arbitrary parameters. 50 00:03:33,960 --> 00:03:39,960 And I would say many physicists have the desire to have a parameter-free theory, where 51 00:03:39,960 --> 00:03:44,960 everything is just required to be the way that it is by pure logic. 52 00:03:44,960 --> 00:03:47,960 And what we see experimentally is that seems to be not the case. 53 00:03:47,960 --> 00:03:54,960 That, in fact, there are these tuning parameters that are what we could call design parameters. 54 00:03:54,960 --> 00:04:00,960 And so, in theological terms, you could say what many physicists want to do, and actually, 55 00:04:00,960 --> 00:04:07,960 Einstein said this explicitly, was he said he would like to prove that God could not have 56 00:04:07,960 --> 00:04:09,960 created the universe any other way. 57 00:04:09,960 --> 00:04:15,960 What we see, actually, is that God, as far as we know, could have done things differently, 58 00:04:15,960 --> 00:04:21,960 that all of these parameters are free parameters, and they're design choices that were made in 59 00:04:21,960 --> 00:04:24,960 making the universe the way that it is. 60 00:04:24,960 --> 00:04:31,960 And so, I just think, eventually, no matter how far we go, we will still see that there 61 00:04:31,960 --> 00:04:38,960 are these design parameters that are free choices of God that are not required by any 62 00:04:38,960 --> 00:04:41,960 kind of logical necessity or geometry or things like that. 63 00:04:41,960 --> 00:04:42,960 So, let's see. 64 00:04:42,960 --> 00:04:43,960 Let's see. 65 00:04:43,960 --> 00:04:44,960 Let's see. 66 00:04:44,960 --> 00:04:45,960 Let's see. 67 00:04:45,960 --> 00:04:46,960 Let's see.