WEBVTT 1 00:00:01.480 --> 00:00:05.599 Welcome to the quark Side. Quantum Physics podcast, an exploration 2 00:00:05.679 --> 00:00:10.839 of the fundamental structure of reality, where quantum laws govern matter, energy, 3 00:00:11.199 --> 00:00:16.239 and information. Here, uncertainty is a feature, not a flaw, 4 00:00:16.719 --> 00:00:19.239 and understanding begins at the smallest scales. 5 00:00:27.559 --> 00:00:29.640 Okay, I have a request. It's a small one, but 6 00:00:29.679 --> 00:00:32.240 I need you to just commit to it for a moment. 7 00:00:32.280 --> 00:00:34.960 I'm okay to stop whatever you're doing just for a second. 8 00:00:35.000 --> 00:00:36.920 Tune everything else out exactly. 9 00:00:37.039 --> 00:00:39.560 Don't look at your phone. If you're driving, well, okay, 10 00:00:39.600 --> 00:00:42.079 please keep your eyes on the road, but just shift 11 00:00:42.119 --> 00:00:44.560 your mental focus. Try to really look at the. 12 00:00:44.759 --> 00:00:46.159 Now, the present moment. 13 00:00:46.320 --> 00:00:48.479 Right, you can watch the second hand on a clock, 14 00:00:48.840 --> 00:00:52.039 or just you know, feel your own heartbeat, don't. Don't 15 00:00:52.799 --> 00:00:56.240 that sensation right there, that feeling of flow. 16 00:00:56.439 --> 00:00:58.600 It's the most fundamental thing we experienced. 17 00:00:58.640 --> 00:01:00.799 We're obsessed with it. We live our entire lives in 18 00:01:00.799 --> 00:01:05.439 this tiny, razor thin slice of reality. We mourn the 19 00:01:05.480 --> 00:01:08.120 past because it's gone, it's buried in memory, and we 20 00:01:08.159 --> 00:01:10.599 stress about the future because it hasn't happened yet. 21 00:01:10.719 --> 00:01:13.879 Right, it is the universal human condition. We treat the 22 00:01:13.920 --> 00:01:17.439 past as a fixed record. It's done, it's written, and 23 00:01:17.480 --> 00:01:20.359 the future, Well, the future is a void. It's a 24 00:01:20.359 --> 00:01:21.959 blank canvas waiting for paint. 25 00:01:22.200 --> 00:01:25.280 That is the common sense view. I mean, that's how 26 00:01:25.280 --> 00:01:27.120 I live my life. Next Tuesday is a ghost. It 27 00:01:27.159 --> 00:01:30.799 doesn't actually exist, it's it's waiting for me to create it. 28 00:01:31.040 --> 00:01:34.280 But and this is why we're here today. We have 29 00:01:34.319 --> 00:01:36.920 a stack of research sitting right here on the desk 30 00:01:37.359 --> 00:01:41.640 that says, my common sense is what's lying to me. 31 00:01:42.000 --> 00:01:43.480 Lying is a polite way to put it. I mean, 32 00:01:43.480 --> 00:01:45.920 if we take the sources we're analyzing today, and they 33 00:01:46.040 --> 00:01:49.840 range from Einstein's relativity to the absolute latest papers on 34 00:01:49.920 --> 00:01:54.879 quantum gravity, that void of next Tuesday might be just 35 00:01:54.920 --> 00:01:58.040 as solid, just as real, and just as already there 36 00:01:58.120 --> 00:01:59.400 as the chair you're sitting. 37 00:01:59.120 --> 00:02:01.640 In right now, which is frankly a terrifying thought. 38 00:02:01.719 --> 00:02:02.680 It's deeply unsettling. 39 00:02:02.760 --> 00:02:05.599 It implies the script is already written. It implies that 40 00:02:05.799 --> 00:02:08.199 while I feel like I'm improvising my life, you know, 41 00:02:08.400 --> 00:02:11.000 make some choices. Yeah, I might just be reciting lines 42 00:02:11.000 --> 00:02:13.680 that were stamped into the fabric of the universe thirteen 43 00:02:13.759 --> 00:02:14.560 billion years ago. 44 00:02:14.639 --> 00:02:16.479 It does, and the more you dig into the physics 45 00:02:16.560 --> 00:02:18.120 of it, the harder it gets to hold onto that 46 00:02:18.120 --> 00:02:20.599 simple idea that time flows at all. We might be 47 00:02:20.680 --> 00:02:23.199 dealing with a universe that is at its most fundamental 48 00:02:23.280 --> 00:02:26.960 level static frozen, frozen, a block of ice where we 49 00:02:27.000 --> 00:02:29.919 are just well trapped in the middle thinking we're swimming. 50 00:02:30.120 --> 00:02:34.360 Okay, so the mission for this whole exploration today is 51 00:02:34.400 --> 00:02:36.479 to see if we can break that block of ice, 52 00:02:37.080 --> 00:02:38.719 or at least understand it. We're going to start with 53 00:02:38.759 --> 00:02:42.120 it intuitive feeling the arrow of time, crash it head 54 00:02:42.120 --> 00:02:43.120 on into general. 55 00:02:42.840 --> 00:02:45.840 Relative, get completely confused by quantum mechanics. 56 00:02:45.360 --> 00:02:47.719 And see if something like free will can even survive 57 00:02:47.759 --> 00:02:49.680 the laws of physics as we understand them. 58 00:02:49.800 --> 00:02:52.520 It is going to be a messy investigation. We are 59 00:02:52.560 --> 00:02:55.360 going to have to dismantle your intuition piece by piece. 60 00:02:55.439 --> 00:02:57.960 Good. I like messy. So let's start with the most 61 00:02:57.960 --> 00:03:01.479 obvious thing, the arrow me This is the most tangible, 62 00:03:01.680 --> 00:03:04.919 undeniable proof that time exists and that it moves in 63 00:03:04.919 --> 00:03:07.960 one direction. Okay, I drop a coffee mug, It falls, 64 00:03:08.000 --> 00:03:10.759 it hits the floor, and it shatters into a thousand pieces. 65 00:03:11.520 --> 00:03:14.639 I have never not once in my entire life see 66 00:03:14.639 --> 00:03:17.240 a pile of ceramic shards on the floor suddenly jump 67 00:03:17.280 --> 00:03:19.479 up and assemble themselves back into a perfect mug. 68 00:03:20.039 --> 00:03:23.360 Right, you are describing the macroscopic world, the world of 69 00:03:23.400 --> 00:03:27.319 big things, mugs, cars, people, omelets, And in that world 70 00:03:27.319 --> 00:03:31.360 the arrow is absolutely undeniable. Events flow from order to disorder. 71 00:03:31.719 --> 00:03:33.719 We see effects follow their causes. 72 00:03:34.000 --> 00:03:38.159 But the sources we're looking at highlight this massive contradiction 73 00:03:38.520 --> 00:03:41.520 right out of the gate. They claim the fundamental laws 74 00:03:41.800 --> 00:03:45.240 of physics they don't care about that arrow at. 75 00:03:45.080 --> 00:03:49.159 All, And that is the reversibility paradox. This is really 76 00:03:49.159 --> 00:03:51.599 the first major hurdle we have to clear in this 77 00:03:51.680 --> 00:03:55.120 whole discussion. If you zoom in, and I mean way 78 00:03:55.319 --> 00:03:58.120 way into the atoms that are making up that coffee mug. 79 00:03:58.400 --> 00:04:01.240 Let's say you could film two of those out I'm colliding. 80 00:04:00.840 --> 00:04:02.719 Okay, just two particles bouncing off each other. 81 00:04:02.719 --> 00:04:04.840 They bounce off each other. Now play that film backward. 82 00:04:04.919 --> 00:04:07.319 It would look exactly the same. They'd just be coming 83 00:04:07.360 --> 00:04:09.280 from different directions and bounce off each other again. 84 00:04:09.360 --> 00:04:13.599 Precisely, the laws of physics don't care. Newtonian physics, Maxwell's 85 00:04:13.599 --> 00:04:19.360 equations for electromagnetism, even the Schrodinger equation in quantum mechanics, essentially, 86 00:04:19.399 --> 00:04:23.079 all the foundational equations we use to describe reality. They 87 00:04:23.079 --> 00:04:25.360 are time symmetric. They work just as well with a 88 00:04:25.399 --> 00:04:29.079 positive T moving forward or a negative T moving backward. 89 00:04:29.160 --> 00:04:31.279 Waitait, are you actually saying that if I could somehow 90 00:04:31.319 --> 00:04:34.560 reverse the velocity of every single particle in the universe 91 00:04:34.639 --> 00:04:37.000 right now, the mug would unshatter. 92 00:04:37.360 --> 00:04:40.639 In theory, yes, the math allows for it. There is 93 00:04:40.680 --> 00:04:44.360 absolutely nothing in the fundamental laws of motion that forbids 94 00:04:44.399 --> 00:04:48.040 those shards from gathering all their thermal energy, leaping up 95 00:04:48.120 --> 00:04:51.480 and fusing back into a perfect mug. The energy transfer, 96 00:04:51.800 --> 00:04:54.519 the momentum, it all works perfectly in reverse. 97 00:04:55.079 --> 00:04:58.680 That sounds completely insane. I mean, it feels wrong on 98 00:04:58.720 --> 00:05:01.839 a gut level. The the math says the mug can unshatter. 99 00:05:01.920 --> 00:05:06.000 Why doesn't it ever? Is physics just lazy? Why do 100 00:05:06.079 --> 00:05:07.360 we never ever see this happen. 101 00:05:07.560 --> 00:05:11.399 It's not laziness, it's statistics. It's just probability on an 102 00:05:11.480 --> 00:05:14.160 unimaginable scale. And this is where we have to talk 103 00:05:14.160 --> 00:05:17.879 about the physicist Ludwig Boltzmann and his concept of entropy. 104 00:05:17.959 --> 00:05:21.879 The universe tends toward disorder. Yeah, the messy room analogy. 105 00:05:21.519 --> 00:05:23.439 Exactly, But we need to go deeper than just saying 106 00:05:23.480 --> 00:05:26.000 things get messy to really get it. We need to 107 00:05:26.000 --> 00:05:29.279 talk about the difference between micro states and macro states. 108 00:05:29.519 --> 00:05:31.199 Okay, lay that out for us. I've heard the messi 109 00:05:31.279 --> 00:05:33.879 room analogy a thousand times, but give me the technical version. 110 00:05:34.079 --> 00:05:35.319 What's the real engine behind this? 111 00:05:35.519 --> 00:05:37.720 Okay, So think of your coffee mug again. The macro 112 00:05:37.800 --> 00:05:40.839 state is the description whole mug. It looks like a mug. 113 00:05:40.879 --> 00:05:41.720 You can drink from it. 114 00:05:41.720 --> 00:05:42.959 It's a mug, simple enough. 115 00:05:43.079 --> 00:05:47.279 But to achieve that specific shape, that whole mug macro state, 116 00:05:47.839 --> 00:05:50.560 the trillions and trillions of atoms inside it have to 117 00:05:50.560 --> 00:05:53.000 be arranged in a very very specific way. They have 118 00:05:53.040 --> 00:05:56.000 to be bonded here, not there. The handle atoms have 119 00:05:56.040 --> 00:05:57.319 to be with the handle atoms. 120 00:05:57.519 --> 00:06:00.319 So there are very few ways for all those atoms 121 00:06:00.360 --> 00:06:01.959 to be arranged and still be called a mug. 122 00:06:02.120 --> 00:06:06.680 Correct. A relatively low number of posttle micro states correspond 123 00:06:06.759 --> 00:06:09.399 to the macro state. Whole mug. Now, think of the 124 00:06:09.399 --> 00:06:11.480 pile of shards on the floor. That is the macro state, 125 00:06:11.639 --> 00:06:15.519 broken mug, chaos, a mess. But think about the atoms. Now, 126 00:06:15.639 --> 00:06:18.560 you can rearrange those shards in a billion different patterns 127 00:06:18.560 --> 00:06:20.360 on the floor and it still just looks like a 128 00:06:20.399 --> 00:06:22.839 pile of shards. You can move the atoms around within 129 00:06:22.879 --> 00:06:25.000 the shods, you can twist them, scatter them across the 130 00:06:25.120 --> 00:06:27.399 entire room. It's still just a broken mug. 131 00:06:28.000 --> 00:06:30.199 I see where you're going with this. There are vastly 132 00:06:30.279 --> 00:06:32.120 more ways for something to be broken than for. 133 00:06:32.079 --> 00:06:35.439 It to be whole, trillions upon trillions upon trillions more ways. 134 00:06:35.480 --> 00:06:38.560 It's not even close. So as the system evolves over time, 135 00:06:38.639 --> 00:06:42.279 as particles jiggle and move around purely by chance, it 136 00:06:42.360 --> 00:06:46.680 is just overwhelmingly, staggeringly likely to move toward the state 137 00:06:46.720 --> 00:06:49.959 that has more possibilities, more available micro states. 138 00:06:50.160 --> 00:06:52.399 So the arrow of time isn't a force. It's not 139 00:06:52.480 --> 00:06:54.560 some cosmic river pushing us forward. 140 00:06:54.720 --> 00:06:57.079 No, that's the big takeaway. It's just the law of 141 00:06:57.160 --> 00:07:00.439 large numbers playing out. We are drifting from the incredibly 142 00:07:00.560 --> 00:07:04.199 unlikely state, which we call order, to the ridiculously likely stay, 143 00:07:04.199 --> 00:07:07.439 which we call disorder. We perceived the statistical drift as 144 00:07:07.519 --> 00:07:10.879 time flowing, but really it's just things shuffling into more 145 00:07:10.920 --> 00:07:13.160 probable configurations. 146 00:07:12.480 --> 00:07:16.920 That is slightly depressing. So our entire experience of past, present, 147 00:07:16.959 --> 00:07:20.240 and future is just us losing a statistical game against 148 00:07:20.279 --> 00:07:20.800 the universe. 149 00:07:21.000 --> 00:07:24.600 Essentially, Yes, but this realization leads to the biggest, most 150 00:07:24.639 --> 00:07:28.680 profound problem in all of cosmology. If time is just 151 00:07:28.720 --> 00:07:32.439 a one way slide toward disorder, that implies we must 152 00:07:32.439 --> 00:07:34.519 have started at the very top of the slide, the 153 00:07:34.560 --> 00:07:37.199 Big Bang, the Big Bank. The sources call this the 154 00:07:37.319 --> 00:07:40.920 past hypothesis. For the arrow of time to even exist today, 155 00:07:41.120 --> 00:07:43.519 for mugs to break, and for us to remember yesterday, 156 00:07:43.800 --> 00:07:46.000 the universe at the moment of the Big Bang must 157 00:07:46.000 --> 00:07:50.040 have had an entropye so low, so incredibly ordered, that 158 00:07:50.120 --> 00:07:54.199 the odds of it happening by chance are well astronomical 159 00:07:54.279 --> 00:07:55.560 doesn't even begin to cover it. 160 00:07:55.680 --> 00:07:58.000 I saw a number in the notes attributed to the 161 00:07:58.000 --> 00:08:01.000 physicist Roger Penrose. Honestly thought it was a typo. 162 00:08:01.160 --> 00:08:04.199 It wasn't a typo. Pennos calculated the probability of our 163 00:08:04.279 --> 00:08:07.639 universe starting in such a low entropy state by random chance. 164 00:08:07.879 --> 00:08:10.240 The number is one in ten to the power of 165 00:08:10.240 --> 00:08:12.279 ten to the power of one hundred and twenty three. 166 00:08:12.399 --> 00:08:14.279 Can you even visualize a number like that? Is there 167 00:08:14.279 --> 00:08:15.199 an analogy for it? 168 00:08:15.480 --> 00:08:18.639 No, there are not enough particles in the entire known 169 00:08:18.720 --> 00:08:20.959 universe to write the zeros of that number on them. 170 00:08:21.240 --> 00:08:24.560 It is the working definition of a statistical miracle. It 171 00:08:24.680 --> 00:08:27.680 suggests that the beginning was special. It was highly tuned, 172 00:08:27.959 --> 00:08:29.160 incredibly specific. 173 00:08:29.439 --> 00:08:31.600 So the only reason I can remember yesterday, and the 174 00:08:31.600 --> 00:08:34.799 only reason eggs break and never unbreak, is because the 175 00:08:34.799 --> 00:08:38.000 Big Bang was, for some unknown reason, weirdly tidy. 176 00:08:38.399 --> 00:08:41.200 That is what some call the cosmological brute fact. We 177 00:08:41.279 --> 00:08:44.600 are surfing the wave of that initial, unexplained order. But 178 00:08:44.679 --> 00:08:48.360 here's the crucial catch. Entropy explains the direction of time, 179 00:08:48.559 --> 00:08:51.240 why we go from past to future, but it doesn't 180 00:08:51.320 --> 00:08:53.080 explain the existence of time. 181 00:08:53.279 --> 00:08:56.120 Right Okay, just because my room is getting messier doesn't 182 00:08:56.120 --> 00:08:58.519 prove that next Tuesday is already built and waiting for me. 183 00:08:58.759 --> 00:09:00.720 It just means that if I get to next Tuesday, 184 00:09:01.000 --> 00:09:03.799 my room will probably be messier than it is today exactly. 185 00:09:04.360 --> 00:09:07.000 Entropy is a signpost pointing the way, but it isn't 186 00:09:07.000 --> 00:09:10.679 the road itself. To understand the road. To really grapple 187 00:09:10.720 --> 00:09:13.519 with whether the future actually exists right now, we have 188 00:09:13.600 --> 00:09:16.360 to leave thermodynamics behind and bring in the heavy hitter. 189 00:09:16.879 --> 00:09:19.159 We have to bring in Albert Einstein. 190 00:09:18.799 --> 00:09:20.360 The presentism Killer. 191 00:09:20.360 --> 00:09:24.320 A very fitting nickname. Before Einstein, pretty much everyone, including 192 00:09:24.320 --> 00:09:29.159 Isaac Newton, thought time was this absolute universal clock TikTok TikTok, 193 00:09:29.240 --> 00:09:30.720 everywhere in the universe at the same time. 194 00:09:30.919 --> 00:09:34.559 A universal now God's wristwatch. So if it's twelve pointy 195 00:09:34.679 --> 00:09:37.639 zero pm here on Earth, it's twelve point zero pm 196 00:09:37.720 --> 00:09:40.039 on Mars, and it's twelve point zero zero pm in 197 00:09:40.080 --> 00:09:43.080 the Andromeda Galaxy, all at the exact same instant. 198 00:09:43.399 --> 00:09:47.480 Right, That feels deeply intuitive, it feels correct. But special 199 00:09:47.519 --> 00:09:50.639 relativity took that universal wristwatch and just smashed it on 200 00:09:50.679 --> 00:09:54.200 the floor. Einstein showed that now is relative. It actually 201 00:09:54.279 --> 00:09:55.759 depends on how fast you're moving. 202 00:09:55.960 --> 00:09:58.159 I always struggle to visualize this part. I get the 203 00:09:58.200 --> 00:10:01.720 time dilation thing. I travel near the speed of light 204 00:10:01.759 --> 00:10:04.399 in a spaceship. I age slower than someone on Earth. 205 00:10:04.919 --> 00:10:08.080 But this is different. This is about simultaneity that was 206 00:10:08.080 --> 00:10:09.279 happening now it is. 207 00:10:09.320 --> 00:10:12.000 It's a much weirder concept. And the best analogy on 208 00:10:12.159 --> 00:10:14.279 the sources we looked at rely on heavily, is to 209 00:10:14.320 --> 00:10:16.200 think of the universe as a loaf of bread. 210 00:10:16.320 --> 00:10:19.240 Okay, I'm listening, I like bread. How does a bakery 211 00:10:19.240 --> 00:10:21.000 item explain the nature of reality? 212 00:10:21.320 --> 00:10:24.840 Imagine the entire universe, all of space and all of time, 213 00:10:25.000 --> 00:10:28.399 is one giant loaf of sour dough. You have length 214 00:10:28.559 --> 00:10:31.639 with height, and the long way from crust to crust 215 00:10:31.759 --> 00:10:34.720 is time. One end of the loaf is the big Bang. 216 00:10:34.720 --> 00:10:36.720 At the other end is the eventual heat death of 217 00:10:36.759 --> 00:10:37.279 the universe. 218 00:10:37.360 --> 00:10:40.600 Okay, so everything that ever was or ever will be 219 00:10:40.720 --> 00:10:43.919 is already baked into this loaf. My birth, this conversation, 220 00:10:44.000 --> 00:10:45.559 the sun exploding. It's all in there. 221 00:10:45.799 --> 00:10:47.759 It's all in there now. If you and I are 222 00:10:47.799 --> 00:10:50.799 standing still relative to each other, our concept of now 223 00:10:51.240 --> 00:10:53.480 is like taking a knife and making a perfectly straight 224 00:10:53.559 --> 00:10:57.000 slice down through the loaf. Everything contained and that one 225 00:10:57.200 --> 00:10:59.720 thin slice is happening at the same time for us. 226 00:11:00.159 --> 00:11:03.080 Cut it's a single snapshot of the entire universe at 227 00:11:03.159 --> 00:11:03.720 one instant. 228 00:11:03.799 --> 00:11:06.440 But here's where Einstein's math comes in. He showed that 229 00:11:06.480 --> 00:11:09.240 if you start moving, even just walking across the room, 230 00:11:09.720 --> 00:11:12.639 your knife angles. You start to cut the loaf at 231 00:11:12.639 --> 00:11:13.159 a slant. 232 00:11:13.320 --> 00:11:13.799 A slant. 233 00:11:13.879 --> 00:11:16.919 What do you mean, Yes, you're slice of now tilts 234 00:11:17.279 --> 00:11:19.919 in the direction you're moving. Your slice tilts into what 235 00:11:20.080 --> 00:11:22.000 for me is the future part of the loaf, and 236 00:11:22.039 --> 00:11:23.639 behind you it tilts into my past. 237 00:11:23.720 --> 00:11:26.200 But if I'm just walking, the tilt must be I 238 00:11:26.240 --> 00:11:29.759 mean infinitesimally small. I walk it maybe three miles an hour. 239 00:11:30.240 --> 00:11:31.480 That can't make a real difference. 240 00:11:31.519 --> 00:11:35.600 It's microscopically immeasurably tiny. On human scales here on Earth, 241 00:11:35.600 --> 00:11:38.759 you would never ever notice. But and this is the 242 00:11:38.879 --> 00:11:42.000 absolute mind blower. Basic geometry tells us that a tiny, 243 00:11:42.080 --> 00:11:46.200 tiny angle, when extended over a massive distance, creates a huge, 244 00:11:46.320 --> 00:11:47.039 huge gap. 245 00:11:47.279 --> 00:11:49.759 Right the liver effect. If I'm holding a laser pointer 246 00:11:50.159 --> 00:11:52.919 and I tilt my wrist just a millimeter, the dot 247 00:11:52.960 --> 00:11:54.679 on the wall across the room might move ten. 248 00:11:54.559 --> 00:11:59.360 Feet exactly that. Now, replace the wall with a galaxy. 249 00:11:59.399 --> 00:12:02.519 This brings us to a thought experiment called the Andromeda paradox. 250 00:12:03.000 --> 00:12:06.039 The Andromeda galaxy is about two point five million light 251 00:12:06.120 --> 00:12:06.960 years away from us. 252 00:12:07.039 --> 00:12:08.960 It's very far down the loaf of breath. 253 00:12:08.759 --> 00:12:11.240 Very far down the loaf. Now, imagine there's an alien 254 00:12:11.360 --> 00:12:15.759 invasion fleet in Andromeda right now, in my slice of now, 255 00:12:15.960 --> 00:12:19.279 me standing still on Earth. Those aliens are in a 256 00:12:19.320 --> 00:12:22.159 council meeting debating whether or not to launch their attack 257 00:12:22.200 --> 00:12:23.559 on Earth. They haven't decided yet. 258 00:12:23.600 --> 00:12:26.000 Okay, So for you, the fleet is grounded, the war 259 00:12:26.039 --> 00:12:27.639 hasn't started. The future is open. 260 00:12:27.879 --> 00:12:30.360 Now you stand up, and start walking, just a slow 261 00:12:30.519 --> 00:12:33.919 stroll in the direction of the Andromeda galaxy. Because of 262 00:12:33.919 --> 00:12:37.879 that vast two point five million light year distance, your 263 00:12:38.159 --> 00:12:41.240 slice of reality tilts dramatically by the time it reaches 264 00:12:41.279 --> 00:12:41.960 that galaxy. 265 00:12:42.200 --> 00:12:44.679 How much of a difference does just walking make over 266 00:12:44.720 --> 00:12:45.679 that kind of distance. 267 00:12:46.039 --> 00:12:49.200 It can make a difference of days, maybe even weeks. 268 00:12:49.279 --> 00:12:52.759 So in your now, purely because of your slow walking motion, 269 00:12:53.440 --> 00:12:56.120 your slice cuts through the Andromeda part of the loaf 270 00:12:56.320 --> 00:12:59.240 days after their council meeting. For you, the fleet has 271 00:12:59.240 --> 00:13:01.639 already launched. The decision has been made. It is a 272 00:13:01.759 --> 00:13:02.600 historical fact. 273 00:13:02.639 --> 00:13:05.799 Wait. Stop, this is the part that always breaks my brain. 274 00:13:06.440 --> 00:13:08.799 We are standing right next to each other. I take 275 00:13:08.840 --> 00:13:11.879 one step forward, and for me an alien invasion has 276 00:13:11.879 --> 00:13:15.519 already begun. But for you, who's standing still, yeah, there's 277 00:13:15.519 --> 00:13:16.080 still peace. 278 00:13:16.399 --> 00:13:18.879 Correct. And to make it even weirder, if you were 279 00:13:18.919 --> 00:13:21.840 to turn around and walk away from Andromeda, your slice 280 00:13:21.840 --> 00:13:24.120 would tilt the other way into their past. For you, 281 00:13:24.200 --> 00:13:26.840 the council meeting hasn't even been proposed yet, the idea 282 00:13:26.879 --> 00:13:28.799 of invading Earth doesn't exist. 283 00:13:29.200 --> 00:13:32.679 So in this one spot right here, we have three 284 00:13:32.720 --> 00:13:36.120 completely contradictory realities, all existing at the same time the 285 00:13:36.159 --> 00:13:38.440 fleet is launching, the fleet is grounded, and the fleet 286 00:13:38.480 --> 00:13:40.440 isn't even a thought yet. How can that be right? 287 00:13:40.679 --> 00:13:43.679 And that's the trap, that's the part that kills presentism. 288 00:13:44.159 --> 00:13:46.840 If the invasion is a real historical event for you 289 00:13:47.039 --> 00:13:50.360 and we inhabit the same physical universe, it implies that 290 00:13:50.679 --> 00:13:53.840 event is sitting there in space time. It has a coordinate. 291 00:13:53.879 --> 00:13:56.000 You're just viewing it from a different angle. You can 292 00:13:56.039 --> 00:13:59.799 no longer say only the present exists, because your present 293 00:13:59.840 --> 00:14:01.679 is my future and someone else's past. 294 00:14:01.960 --> 00:14:03.960 It's like a statue. I'm looking at the front, you're 295 00:14:04.000 --> 00:14:06.120 looking at the side, but the whole statue is solid, 296 00:14:06.399 --> 00:14:07.559 it's already fully carved. 297 00:14:07.919 --> 00:14:10.360 That is the block universe in a nutshell. If you 298 00:14:10.440 --> 00:14:14.480 accept the core tenets of special relativity, you are almost 299 00:14:14.639 --> 00:14:17.559 forced logically to accept that the future is just as 300 00:14:17.639 --> 00:14:21.159 real and fixed as the past. It's all just geometry. 301 00:14:21.240 --> 00:14:24.720 That makes me feel incredibly claustrophobic. It implies the future 302 00:14:24.759 --> 00:14:26.799 is just a city down the road. We haven't driven 303 00:14:26.799 --> 00:14:28.960 there yet, but the buildings are already built, the stop 304 00:14:29.000 --> 00:14:32.480 lights are already timed, everything is in place precisely. 305 00:14:33.000 --> 00:14:37.080 This philosophical view is called eternalism. The past, the present, 306 00:14:37.159 --> 00:14:41.039 and the future are all equally real, all coexisting in 307 00:14:41.080 --> 00:14:45.679 this four dimensional block. Our feeling of now is just 308 00:14:45.799 --> 00:14:49.360 an illusion of consciousness, like a spotlight moving across the 309 00:14:49.399 --> 00:14:51.120 stage that's already been built and set. 310 00:14:51.320 --> 00:14:54.320 But hold on. If that's true, then my choice to 311 00:14:54.320 --> 00:14:56.759 interrupt you just now wasn't really a choice. It was 312 00:14:57.320 --> 00:14:59.279 It was just a pre written line in the block. 313 00:14:59.159 --> 00:15:02.120 Under a strict intern interpretation of general relativity. Yes, it 314 00:15:02.159 --> 00:15:04.399 was a fixed point in forty space time that was 315 00:15:04.440 --> 00:15:05.279 always going to happen. 316 00:15:05.360 --> 00:15:08.159 Iest I refuse to accept that there has to be 317 00:15:08.240 --> 00:15:11.799 an escape patch. We are just creatures of relativity. We 318 00:15:11.799 --> 00:15:14.879 have quantum mechanics, and quantum mechanics is famous for being 319 00:15:14.879 --> 00:15:18.559 fundamentally weird and random. Doesn't that randomness save us from 320 00:15:18.600 --> 00:15:18.960 the block? 321 00:15:19.240 --> 00:15:22.240 Ah? And this is the quantum wrench in the gears 322 00:15:22.279 --> 00:15:25.559 of the whole machine. Just when relativity convinces us that 323 00:15:25.600 --> 00:15:29.039 the future is fixed and deterministic, quantum mechanics enters the 324 00:15:29.080 --> 00:15:31.480 chat and makes everything fuzzy and uncertain. 325 00:15:31.080 --> 00:15:33.440 Again, because in the quantum world, things aren't fixed until 326 00:15:33.480 --> 00:15:35.399 you look at them, right, That's the basic idea. 327 00:15:35.600 --> 00:15:39.360 Broadly speaking, Yes, on one side, we have the Schrodinger equation, 328 00:15:39.759 --> 00:15:43.080 which describes how a quantum system like an electron in 329 00:15:43.120 --> 00:15:47.720 a cloud of possibility, evolves over time, and interestingly, the 330 00:15:47.759 --> 00:15:51.000 equation itself, the evolution of that wave of possibility is 331 00:15:51.080 --> 00:15:56.600 perfectly deterministic. It's predictable until measurement. The famous collapse of 332 00:15:56.639 --> 00:15:59.480 the wave function when you interact with the system. When 333 00:15:59.480 --> 00:16:01.879 you measure the electron to see where it is, the 334 00:16:02.039 --> 00:16:05.440 entire wave function collapses from a clide of possibilities into 335 00:16:05.480 --> 00:16:08.559 a single, definite state, and this collapse appears to be 336 00:16:08.679 --> 00:16:10.919 completely random, an irreversible. 337 00:16:11.080 --> 00:16:14.519 Okay, So if the fundamental building blocks of reality are 338 00:16:14.600 --> 00:16:17.399 essentially slipping coins every time they interact, how can the 339 00:16:17.399 --> 00:16:19.679 future possibly be fixed? Let's say I have a choice 340 00:16:19.679 --> 00:16:22.320 to eat a burger or a salad for lunch. That 341 00:16:22.519 --> 00:16:25.320 choice ultimately depends on some neuron firing in my brain, 342 00:16:25.759 --> 00:16:28.960 and that neuron firing depends on some quantum event. Isn't 343 00:16:28.960 --> 00:16:30.120 the future genuinely open? 344 00:16:30.159 --> 00:16:32.440 Then that is the great hope for those who want 345 00:16:32.440 --> 00:16:35.360 to save free will in an open future. But and 346 00:16:35.399 --> 00:16:37.360 I hate to be the bearer of bad news again, 347 00:16:37.919 --> 00:16:41.080 it depends entirely on which side of the quantum wars 348 00:16:41.120 --> 00:16:44.519 you're on the interpretation of what quantum mechanics is actually 349 00:16:44.519 --> 00:16:47.159 telling us about reality matters immensely here. 350 00:16:47.240 --> 00:16:49.480 Okay, let's break down the camps, who are the main 351 00:16:49.600 --> 00:16:51.000 combatants in these wars. 352 00:16:51.320 --> 00:16:53.679 Well, first, you have the oldest, and you know, the 353 00:16:53.799 --> 00:16:57.120 standard textbook view. It's called the Cockenhagen interpretation from Bore 354 00:16:57.240 --> 00:17:00.480 and his colleagues. It basically says, the wave function isn't 355 00:17:00.559 --> 00:17:03.559 real reality, it's just a mathematical tool we use for 356 00:17:03.600 --> 00:17:07.079 making predictions. Reality is created in the act of measurement. 357 00:17:07.880 --> 00:17:11.079 So in this view, the future is genuinely open because 358 00:17:11.119 --> 00:17:14.279 nothing is decided until the moment of collapse. The electron 359 00:17:14.400 --> 00:17:15.799 wasn't anywhere until we looked. 360 00:17:15.960 --> 00:17:18.480 Okay, so that's a point for Team free Will. The 361 00:17:18.519 --> 00:17:22.279 bloc universe is cracked, the future is unwritten perhaps. 362 00:17:23.079 --> 00:17:26.640 But then you have the second camp, the hidden variables interpretation, 363 00:17:26.920 --> 00:17:30.519 which was famously championed by physicists like David Boehm. They 364 00:17:30.519 --> 00:17:33.960 looked at that random electron and essentially said Einsteinstein's line, 365 00:17:34.160 --> 00:17:35.319 God does not play. 366 00:17:35.079 --> 00:17:38.160 Dice, meaning that the randomness is just an illusion. It's 367 00:17:38.160 --> 00:17:39.240 fake exactly. 368 00:17:40.000 --> 00:17:42.799 This view says that the particle always had a definite 369 00:17:42.839 --> 00:17:45.599 position and a definite path. We just didn't know the 370 00:17:45.720 --> 00:17:49.039 hidden variables that were guiding it. It's like a complex 371 00:17:49.079 --> 00:17:51.440 magic trick. It looks like magic to the audience because 372 00:17:51.480 --> 00:17:53.759 they can't see that the hidden wires and mirrors, but 373 00:17:53.799 --> 00:17:55.960 the magician knows exactly where the card is going to 374 00:17:56.039 --> 00:17:56.359 end up. 375 00:17:56.519 --> 00:18:00.960 So if the hidden variables interpretation is correct, and all 376 00:18:00.960 --> 00:18:04.720 that quantum weirdness is just a sign of our ignorance, 377 00:18:04.799 --> 00:18:07.640 and we're back to a fully deterministic universe, we are. 378 00:18:07.640 --> 00:18:10.480 Right back in the block universe. The future is fixed 379 00:18:10.480 --> 00:18:12.799 and determined. We just can't predict it because we don't 380 00:18:12.799 --> 00:18:13.920 have access to all the data. 381 00:18:14.039 --> 00:18:17.839 That's deeply disappointing. What about the third one, the one 382 00:18:17.880 --> 00:18:19.799 that science fiction absolutely. 383 00:18:19.279 --> 00:18:23.599 Loves, ah the Many World's interpretation. This one is utterly 384 00:18:23.640 --> 00:18:25.680 fascinating when you think about it in terms of time. 385 00:18:25.839 --> 00:18:28.319 It was proposed by Hugh Everett, and it takes the 386 00:18:28.319 --> 00:18:32.920 Schrodinger equation at its word, as the wave function never collapses. 387 00:18:32.400 --> 00:18:35.759 It keeps going. What happens at the measurement, then it branches. 388 00:18:36.519 --> 00:18:40.960 The entire universe splits. Every single possible outcome of a 389 00:18:41.039 --> 00:18:45.160 quantum measurement actually happens. So in your lunch decision, the 390 00:18:45.240 --> 00:18:48.079 universe splits in two. You eat the burger in one branch, 391 00:18:48.400 --> 00:18:51.000 and an identical copy of you eats the salad in 392 00:18:51.079 --> 00:18:51.839 another branch. 393 00:18:51.920 --> 00:18:57.160 So the universe is constantly infinitely splitting into this massive 394 00:18:57.559 --> 00:18:59.279 fractal of different realities and. 395 00:18:59.359 --> 00:19:01.799 Ever growing branching tree of timeline. 396 00:19:01.839 --> 00:19:05.759 Wait a minute, If the universe splits, then the future 397 00:19:05.799 --> 00:19:09.200 isn't a single line anymore. Correct, So does the future 398 00:19:09.200 --> 00:19:12.680 exist in the mini world's view or is it being created? 399 00:19:12.799 --> 00:19:15.960 All of them exist objectively from a god's eye view 400 00:19:16.000 --> 00:19:19.200 of this multiverse. The entire branching structure is a fixed, 401 00:19:19.319 --> 00:19:23.319