1 00:00:55,728 --> 00:00:58,458 The surface of the Earth is far more beautiful... 2 00:00:58,664 --> 00:01:02,395 ...and far more intricate than any lifeless world. 3 00:01:02,601 --> 00:01:04,796 Our planet is graced by life. 4 00:01:05,003 --> 00:01:08,734 And one quality that sets life apart is its complexity... 5 00:01:08,941 --> 00:01:13,537 ...slowly evolved through 4 billion years of natural selection. 6 00:01:15,981 --> 00:01:17,778 You can describe in detail... 7 00:01:17,983 --> 00:01:21,282 ...how a rock is put together in a single paragraph. 8 00:01:21,487 --> 00:01:24,149 But to describe the basic structure of a tree... 9 00:01:24,590 --> 00:01:27,184 ...or a blade of grass or even a one-celled animal... 10 00:01:27,393 --> 00:01:29,554 ...you'd need many volumes. 11 00:01:29,762 --> 00:01:32,162 It takes a great deal of information to make... 12 00:01:32,364 --> 00:01:35,959 ...or even to characterize a living thing. 13 00:01:38,604 --> 00:01:41,129 The measuring rod, the unit of information... 14 00:01:41,340 --> 00:01:44,104 ...is something called the bit. 15 00:01:44,309 --> 00:01:46,504 It's an answer, either yes or no... 16 00:01:46,712 --> 00:01:49,943 ...to one unambiguously phrased question. 17 00:01:50,149 --> 00:01:53,380 So to specify whether a light switch is on or off... 18 00:01:53,585 --> 00:01:55,450 ...requires only a single bit. 19 00:01:55,654 --> 00:01:59,784 To specify something of greater complexity requires more bits. 20 00:01:59,992 --> 00:02:03,086 There's a popular game called 20 Questions... 21 00:02:03,295 --> 00:02:07,231 ...which shows that a great deal can be specified in only 20 bits. 22 00:02:07,433 --> 00:02:09,025 For example... 23 00:02:09,234 --> 00:02:11,225 ...I have something in my hand. 24 00:02:11,437 --> 00:02:12,836 What is it? 25 00:02:13,038 --> 00:02:14,528 Is it alive? Yes. 26 00:02:14,740 --> 00:02:16,037 One bit. 27 00:02:16,241 --> 00:02:18,266 Is it an animal? Nope. 28 00:02:18,477 --> 00:02:19,967 Two bits. 29 00:02:20,212 --> 00:02:22,772 Is it big enough to see? Yep. 30 00:02:23,248 --> 00:02:25,375 Does it grow on the land? Yes. 31 00:02:25,584 --> 00:02:27,984 Is it a cultivated plant? Nope. 32 00:02:28,454 --> 00:02:30,388 Well, with only five bits... 33 00:02:30,589 --> 00:02:33,456 ...we've made substantial progress to figuring out what it is. 34 00:02:33,659 --> 00:02:36,093 With 20 skillfully chosen questions... 35 00:02:36,295 --> 00:02:39,753 ...we could easily whittle all the cosmos down... 36 00:02:40,466 --> 00:02:42,058 ...to a dandelion. 37 00:03:00,686 --> 00:03:03,211 In our explorations of the cosmos... 38 00:03:03,422 --> 00:03:06,516 ...the first step is to ask the right questions. 39 00:03:06,725 --> 00:03:10,422 Then, not with 20 questions, but with billions... 40 00:03:10,629 --> 00:03:14,087 ...we slowly distill from the complexity of the universe... 41 00:03:14,299 --> 00:03:16,233 ...its underlying order. 42 00:03:16,435 --> 00:03:18,960 This game has a serious purpose. 43 00:03:19,171 --> 00:03:22,140 Its name is science. 44 00:03:23,709 --> 00:03:26,576 Out here in the great cosmic dark... 45 00:03:26,778 --> 00:03:29,303 ...there are countless stars and planets... 46 00:03:29,515 --> 00:03:32,712 ...some far older than our solar system. 47 00:03:32,918 --> 00:03:36,547 Though we cannot be certain, the same processes which led on Earth... 48 00:03:36,755 --> 00:03:38,655 ...to the origin of life and intelligence... 49 00:03:38,857 --> 00:03:41,690 ...should've been operating throughout the cosmos. 50 00:03:41,894 --> 00:03:45,796 There may be a million worlds in the Milky Way galaxy alone... 51 00:03:45,998 --> 00:03:47,397 ...which are at this moment... 52 00:03:47,599 --> 00:03:51,330 ...inhabited by other intelligent beings. 53 00:03:58,777 --> 00:04:01,302 What a wonder, what a joy it would be... 54 00:04:01,513 --> 00:04:04,380 ...to know something about non-human intelligence. 55 00:04:04,583 --> 00:04:06,107 And we can. 56 00:04:10,989 --> 00:04:13,457 Here is an exotic inhabited world... 57 00:04:13,659 --> 00:04:15,854 ...mostly covered with a liquid. 58 00:04:20,832 --> 00:04:23,096 We seek the dominant intelligence... 59 00:04:23,302 --> 00:04:26,635 ...that lives beneath its fluid surface. 60 00:04:42,788 --> 00:04:46,224 This ocean of liquid water kilometers deep... 61 00:04:46,425 --> 00:04:49,986 ...is teeming with strange forms of life. 62 00:04:54,533 --> 00:04:58,162 There are communities of transparent beings. 63 00:05:02,608 --> 00:05:05,133 There are societies of creatures which communicate... 64 00:05:05,344 --> 00:05:08,177 ...by changing the patterns on their bodies. 65 00:05:16,188 --> 00:05:19,589 There are beings that give off their own light. 66 00:05:27,032 --> 00:05:30,866 There are hungry flowers that devour passersby... 67 00:05:31,069 --> 00:05:33,094 ...gesticulating trees. 68 00:05:33,472 --> 00:05:36,669 All manner of creatures that seem to violate... 69 00:05:36,875 --> 00:05:40,174 ...the boundaries between plants and animals. 70 00:05:58,730 --> 00:06:01,528 There are beings that flutter through the ocean like... 71 00:06:01,867 --> 00:06:03,960 ...waltzing orchids. 72 00:06:21,153 --> 00:06:23,018 These are a few of the species... 73 00:06:23,221 --> 00:06:26,088 ...that inhabit the water world called Earth. 74 00:06:37,869 --> 00:06:39,302 They're packed with information. 75 00:06:39,838 --> 00:06:42,432 Each one has a rich behavioral repertoire... 76 00:06:42,641 --> 00:06:44,734 ...to ensure its own survival. 77 00:06:53,685 --> 00:06:55,915 But the grandest creatures on the planet... 78 00:06:56,321 --> 00:07:00,052 ...the intelligent and graceful masters of the deep ocean... 79 00:07:00,258 --> 00:07:02,055 ...are the great whales. 80 00:07:02,260 --> 00:07:05,127 They are the largest animals ever to evolve on Earth... 81 00:07:05,330 --> 00:07:08,128 ...larger, by far, than the dinosaurs. 82 00:07:08,333 --> 00:07:11,564 Their ancestors were meat-eating mammals who migrated... 83 00:07:11,770 --> 00:07:16,207 ...70 million years ago in slow steps from the land into the waters. 84 00:07:16,441 --> 00:07:19,069 Whales, like these humpbacks, are still mammals. 85 00:07:19,311 --> 00:07:21,336 We humans have much in common with them. 86 00:07:21,546 --> 00:07:23,207 Mothers suckle infants... 87 00:07:23,415 --> 00:07:26,077 ...there's a long childhood when adults teach the young... 88 00:07:26,284 --> 00:07:29,879 ...and there's a lot of play. These are mammalian characteristics. 89 00:07:30,088 --> 00:07:32,818 Vital if an animal is to learn. 90 00:07:33,024 --> 00:07:34,821 But the sea is murky. 91 00:07:35,026 --> 00:07:36,960 The senses of sight and smell... 92 00:07:37,162 --> 00:07:38,925 ...which work well for mammals on the land... 93 00:07:39,131 --> 00:07:40,689 ...are not much use here. 94 00:07:40,899 --> 00:07:43,663 So the whales evolved an extraordinary ability... 95 00:07:43,869 --> 00:07:46,360 ...to communicate by sound. 96 00:07:46,571 --> 00:07:50,371 For tens of millions of years, the whales had no natural enemies. 97 00:07:50,575 --> 00:07:54,136 And then, a new and alien and deadly creature... 98 00:07:54,379 --> 00:07:58,247 ...suddenly appeared on the placid surface of the ocean. 99 00:08:11,963 --> 00:08:16,332 These often noisy and occasionally deadly objects... 100 00:08:16,535 --> 00:08:20,528 ...first appeared in large numbers only a few centuries ago. 101 00:08:20,739 --> 00:08:22,331 They are artifacts... 102 00:08:22,541 --> 00:08:24,532 ...manufactured by land creatures... 103 00:08:24,743 --> 00:08:27,143 ...whose ancestors last lived in the oceans... 104 00:08:27,345 --> 00:08:29,836 ...350 million years ago. 105 00:08:43,929 --> 00:08:45,624 This particular one, however... 106 00:08:45,831 --> 00:08:48,925 ...is on a mission of understanding. 107 00:08:51,903 --> 00:08:54,872 It's called the Regina Maris... 108 00:08:55,440 --> 00:08:56,907 ...the "Queen of the Sea." 109 00:08:57,108 --> 00:09:01,442 And one of its jobs is to record the sounds of the whales. 110 00:09:04,749 --> 00:09:07,741 Some whale sounds are called songs... 111 00:09:07,953 --> 00:09:10,888 ...but we really don't know what their contents are. 112 00:09:11,089 --> 00:09:13,387 They range in frequency... 113 00:09:13,592 --> 00:09:16,254 ...over a broadband of sounds... 114 00:09:16,461 --> 00:09:18,827 ...down to frequencies well below... 115 00:09:19,197 --> 00:09:21,757 ...the lowest sounds the human ear can make out. 116 00:09:21,967 --> 00:09:24,765 A typical whale song lasts maybe 15 minutes. 117 00:09:24,970 --> 00:09:28,064 The longest, perhaps half an hour. 118 00:09:28,273 --> 00:09:32,300 Occasionally, a group of whales will leave their winter waters... 119 00:09:32,544 --> 00:09:34,409 ...in the middle of a song... 120 00:09:34,613 --> 00:09:37,707 ...and six months later they'll return and pick the song up... 121 00:09:37,916 --> 00:09:40,350 ...at precisely the spot that they left it off. 122 00:09:40,552 --> 00:09:41,610 Beat for beat. 123 00:09:41,853 --> 00:09:43,150 Measure for measure. 124 00:09:43,355 --> 00:09:44,879 Sound for sound. 125 00:09:46,558 --> 00:09:50,517 Whales are very good at remembering. 126 00:09:51,162 --> 00:09:53,960 Other times they will come back after... 127 00:09:54,165 --> 00:09:57,134 ...an absence of six months, and the piece will have changed. 128 00:09:57,335 --> 00:10:02,034 A different song will be on the whale hit parade. 129 00:10:03,341 --> 00:10:07,744 Very often the members of the group will sing the same song together. 130 00:10:07,946 --> 00:10:12,883 By some mutual consensus, some collaborative songwriting... 131 00:10:13,184 --> 00:10:17,280 ...the piece changes slowly and often predictably. 132 00:10:17,489 --> 00:10:20,981 I'm not very good at singing the songs of whales... 133 00:10:21,192 --> 00:10:23,057 ...but here's a try. 134 00:10:23,261 --> 00:10:24,819 In January... 135 00:10:25,030 --> 00:10:29,160 ...a tiny fragment of a long whale song... 136 00:10:29,367 --> 00:10:31,028 ...might sound like this. 137 00:10:31,236 --> 00:10:34,103 Whoop. Ahh. 138 00:10:35,106 --> 00:10:38,098 In February, something like this. 139 00:10:38,310 --> 00:10:43,213 Whoop. Ahh. Ahh. 140 00:10:43,682 --> 00:10:46,913 And then in March, as maybe you'd predict... 141 00:10:47,118 --> 00:10:52,021 Whoop. Ahh. Ahh. Ahh. 142 00:10:53,091 --> 00:10:56,652 One additional "ahh" a month. 143 00:11:01,700 --> 00:11:04,396 The complex patterns in the songs of the whales... 144 00:11:04,602 --> 00:11:07,127 ...are sometimes repeated precisely. 145 00:11:07,339 --> 00:11:10,775 If I imagine that the songs of the humpback whale are sung... 146 00:11:10,976 --> 00:11:12,773 ...in a tonal language... 147 00:11:12,978 --> 00:11:15,640 ...then the number of bits of information in one song... 148 00:11:15,847 --> 00:11:18,179 ...is the same as the information content... 149 00:11:18,383 --> 00:11:21,375 ...of the Iliad or the Odyssey. 150 00:11:33,031 --> 00:11:34,692 Is it just a romantic notion... 151 00:11:34,899 --> 00:11:37,367 ...that the whales and their cousins, the dolphins... 152 00:11:37,569 --> 00:11:41,562 ...might have something akin to epic poetry? 153 00:12:06,264 --> 00:12:10,860 What might whales or dolphins have to talk or sing about? 154 00:12:11,069 --> 00:12:13,094 They have no manipulative organs. 155 00:12:13,304 --> 00:12:17,434 They can't make great engineering constructs as we can. 156 00:12:18,510 --> 00:12:20,205 But they're social creatures. 157 00:12:20,412 --> 00:12:22,880 They hunt and swim, fish... 158 00:12:23,081 --> 00:12:25,208 ...browse, frolic, mate, play... 159 00:12:26,151 --> 00:12:27,812 ...run from predators. 160 00:12:28,019 --> 00:12:29,919 There might be a lot to talk about. 161 00:12:45,570 --> 00:12:49,529 The great danger for the whales is a newcomer... 162 00:12:49,741 --> 00:12:53,575 ...an upstart animal only recently through technology... 163 00:12:53,778 --> 00:12:56,372 ...become competent in the oceans: 164 00:12:57,749 --> 00:12:59,876 A creature called man. 165 00:13:01,152 --> 00:13:03,882 For 99.99% of the history of whales... 166 00:13:04,089 --> 00:13:06,387 ...there were no humans in the deep oceans. 167 00:13:06,991 --> 00:13:09,016 During this period, the whales evolved... 168 00:13:09,227 --> 00:13:11,525 ...their extraordinary communications system. 169 00:13:11,729 --> 00:13:15,859 Some whales emit extremely loud sounds at a frequency of 20 hertz. 170 00:13:16,067 --> 00:13:20,265 A hertz, which is spelled H-E-R-T-Z, is a unit of sound frequency... 171 00:13:20,472 --> 00:13:25,068 ...and it represents one sound wave entering my ear every second. 172 00:13:25,276 --> 00:13:27,870 A frequency of 2000 hertz sounds... 173 00:13:28,079 --> 00:13:29,808 ...and looks like this. 174 00:13:33,084 --> 00:13:35,211 200 hertz, like this. 175 00:13:36,855 --> 00:13:38,413 And 20 hertz, like this. 176 00:13:38,623 --> 00:13:40,454 Although your TV set may not transmit... 177 00:13:40,658 --> 00:13:43,650 ...sounds with frequencies as low as 20 hertz. 178 00:13:44,696 --> 00:13:47,256 The American biologist Roger Payne has calculated... 179 00:13:47,465 --> 00:13:51,265 ...that there's a deep sound channel in the ocean at these frequencies... 180 00:13:51,469 --> 00:13:54,131 ...through which two whales could communicate... 181 00:13:54,339 --> 00:13:55,931 ...anywhere in the world. 182 00:13:56,141 --> 00:14:00,976 One whale might be off the Ross Ice Shelf then in Antarctica... 183 00:14:01,179 --> 00:14:04,842 ...and communicate with another whale in the Aleutians in Alaska. 184 00:14:05,183 --> 00:14:07,981 For most of their history, whales seem to have established... 185 00:14:08,186 --> 00:14:11,314 ...a global communications network. 186 00:14:13,057 --> 00:14:15,719 What two whales might have to say to each other... 187 00:14:15,927 --> 00:14:20,261 ...separated by 15,000 kilometers, I haven't the foggiest idea. 188 00:14:20,465 --> 00:14:22,865 But maybe it's a love song... 189 00:14:23,067 --> 00:14:26,730 ...cast into the vastness of the deep. 190 00:14:30,842 --> 00:14:34,005 Now, this calculation on the range of whale communications... 191 00:14:34,212 --> 00:14:37,238 ...assumes that the oceans are quiet. 192 00:14:43,855 --> 00:14:46,824 But in the 19th century, sailing ships like this one... 193 00:14:47,158 --> 00:14:49,718 ...began to be replaced by steamships... 194 00:14:49,928 --> 00:14:53,193 ...another invention of those strange land animals. 195 00:14:53,398 --> 00:14:57,164 Commercial and military vessels became more abundant. 196 00:14:59,003 --> 00:15:01,164 The noise pollution in the sea got much worse... 197 00:15:01,773 --> 00:15:04,867 ...especially at a frequency of 20 hertz. 198 00:15:08,580 --> 00:15:11,606 The crew of this vessel try consciously to keep her quiet. 199 00:15:11,816 --> 00:15:12,942 But when its engine is on... 200 00:15:13,151 --> 00:15:15,711 ...it gets very loud at a frequency of 20 hertz. 201 00:15:17,422 --> 00:15:19,617 Whales communicating across the oceans... 202 00:15:19,824 --> 00:15:22,759 ...must've experienced greater and greater difficulties. 203 00:15:22,961 --> 00:15:25,088 The distance over which they could communicate... 204 00:15:25,296 --> 00:15:27,764 ...must have steadily decreased. 205 00:15:28,933 --> 00:15:30,628 Two hundred years ago... 206 00:15:30,835 --> 00:15:33,770 ...a typical distance that some whales could communicate across... 207 00:15:33,972 --> 00:15:36,941 ...was perhaps 10,000 kilometers. 208 00:15:37,141 --> 00:15:39,439 Today, on a typical day... 209 00:15:39,644 --> 00:15:43,273 ...the corresponding number is perhaps a few 100 kilometers. 210 00:15:43,481 --> 00:15:46,678 We have cut off the whales from themselves. 211 00:15:46,884 --> 00:15:49,478 Creatures which were freely communicating... 212 00:15:49,687 --> 00:15:51,484 ...for tens of millions of years... 213 00:15:51,689 --> 00:15:54,715 ...have now effectively been silenced. 214 00:16:00,531 --> 00:16:02,465 And we've done worse than that... 215 00:16:02,667 --> 00:16:05,067 ...because there persists till this day... 216 00:16:05,270 --> 00:16:08,865 ...a traffic in the dead bodies of whales. 217 00:16:09,073 --> 00:16:12,167 There are humans who gratuitously hunt and slaughter whales... 218 00:16:12,377 --> 00:16:17,314 ...and market the products for dog food or lipstick. 219 00:16:18,216 --> 00:16:22,516 Many nations understand why whale murder is monstrous... 220 00:16:22,720 --> 00:16:25,211 ...but the traffic continues chiefly... 221 00:16:25,423 --> 00:16:28,984 ...by Japan and Norway and the Soviet Union. 222 00:16:29,894 --> 00:16:32,089 We use "monster" to describe an animal... 223 00:16:32,330 --> 00:16:35,493 ...somehow different from us, somehow scary. 224 00:16:36,301 --> 00:16:38,269 But who's the more monstrous... 225 00:16:38,469 --> 00:16:40,562 ...the whales, who ask to be left alone... 226 00:16:40,772 --> 00:16:43,434 ...to sing their rich and plaintive songs... 227 00:16:43,708 --> 00:16:47,667 ...or the humans, who set out to hunt them and destroy them... 228 00:16:47,879 --> 00:16:51,975 ...and have brought many whale species close to the edge of extinction? 229 00:16:54,385 --> 00:16:57,912 We're interested in communication with extraterrestrial intelligence. 230 00:16:58,122 --> 00:17:00,022 Wouldn't a good beginning be... 231 00:17:00,224 --> 00:17:03,022 ...better communication with terrestrial intelligence... 232 00:17:03,227 --> 00:17:06,594 ...with other human beings of different cultures and languages... 233 00:17:06,798 --> 00:17:08,993 ...with the great apes, with the dolphins... 234 00:17:09,200 --> 00:17:11,691 ...but particularly with the whales? 235 00:17:40,698 --> 00:17:44,293 To survive, a whale must know how to do things. 236 00:17:44,502 --> 00:17:46,936 This knowledge is stored in two principal ways... 237 00:17:47,138 --> 00:17:50,733 ...in the whale's genes and in their very large brains. 238 00:17:50,942 --> 00:17:52,807 We can think of their genes and brains... 239 00:17:53,010 --> 00:17:55,911 ...as something like libraries inside their bodies. 240 00:17:56,114 --> 00:17:58,878 The information in the DNA, the genetic information... 241 00:17:59,083 --> 00:18:00,880 ...includes how to nurse... 242 00:18:01,085 --> 00:18:03,246 ...how to convert shrimp into blubber... 243 00:18:03,454 --> 00:18:07,390 ...how to hold your breath on a dive one kilometer below the surface. 244 00:18:07,592 --> 00:18:10,425 The information in the brains, the learned information... 245 00:18:10,628 --> 00:18:12,186 ...involves such things as... 246 00:18:12,397 --> 00:18:13,455 ...who's your mother... 247 00:18:13,664 --> 00:18:17,122 ...or what the meaning is of that song we're hearing just now. 248 00:18:20,304 --> 00:18:23,296 The gene library of whales and people... 249 00:18:23,508 --> 00:18:24,998 ...and everybody else on Earth... 250 00:18:25,209 --> 00:18:26,801 ...is made of DNA. 251 00:18:27,011 --> 00:18:29,104 The only function of this complex molecule... 252 00:18:29,313 --> 00:18:33,147 ...is to store and copy information. 253 00:18:37,155 --> 00:18:41,114 We see here the set of instructions in human DNA... 254 00:18:41,325 --> 00:18:45,989 ...written in a language billions of years older than any human tongue. 255 00:18:46,197 --> 00:18:48,131 Each colored cluster of atoms... 256 00:18:48,332 --> 00:18:51,768 ...is a letter in the genetic alphabet: The language of life. 257 00:18:51,969 --> 00:18:53,436 There are billions of letters... 258 00:18:53,638 --> 00:18:56,903 ...many billions of bits of information. 259 00:18:57,408 --> 00:18:59,535 If you came from somewhere very different... 260 00:18:59,744 --> 00:19:02,804 ...you wouldn't be able to specify a whale or a person... 261 00:19:03,014 --> 00:19:06,450 ...in a game of 20 Questions with only 20 bits. 262 00:19:06,651 --> 00:19:10,052 But a game called 10 Billion Questions... 263 00:19:10,254 --> 00:19:11,949 ...might just work. 264 00:19:12,156 --> 00:19:13,487 Every organism on Earth... 265 00:19:13,691 --> 00:19:16,455 ...contains as its inheritance and legacy... 266 00:19:16,661 --> 00:19:18,526 ...a portable library. 267 00:19:18,729 --> 00:19:23,098 And the more bits of information you have, the more you can do. 268 00:19:26,737 --> 00:19:28,932 The simplest organism, a virus... 269 00:19:29,140 --> 00:19:31,370 ...needs only about 10,000 bits. 270 00:19:31,576 --> 00:19:35,637 Equal to the amount of information on one page of an average book. 271 00:19:35,847 --> 00:19:37,576 These are all the instructions it needs... 272 00:19:37,782 --> 00:19:40,615 ...to infect some other organism and to reproduce itself... 273 00:19:40,818 --> 00:19:44,219 ...which are the only things that viruses are any good at. 274 00:19:44,422 --> 00:19:47,949 A bacterium uses roughly a million bits of information... 275 00:19:48,159 --> 00:19:49,922 ...about 100 printed pages. 276 00:19:50,127 --> 00:19:52,391 Bacteria have a lot more to do than viruses. 277 00:19:52,597 --> 00:19:57,125 They're not thoroughgoing parasites. Bacteria have to make a living. 278 00:20:00,872 --> 00:20:04,000 What about a free-swimming one-celled amoeba? 279 00:20:04,208 --> 00:20:06,472 These creatures are also microscopic... 280 00:20:06,944 --> 00:20:09,105 ...but in the realm of one-celled animals... 281 00:20:09,313 --> 00:20:10,746 ...they are giants. 282 00:20:10,948 --> 00:20:13,974 The whales of the microbial world. 283 00:20:14,185 --> 00:20:18,713 Each contains about 400 million bits in its DNA... 284 00:20:18,923 --> 00:20:22,984 ...the equivalent of about 80 volumes of 500 pages each. 285 00:20:23,194 --> 00:20:25,822 That's how much information it takes to make an amoeba... 286 00:20:26,030 --> 00:20:30,967 ...a creature like a small city wandering through a drop of water. 287 00:20:34,739 --> 00:20:36,900 And what about a whale or a human being? 288 00:20:37,108 --> 00:20:38,973 Well, the answer seems to be... 289 00:20:39,176 --> 00:20:43,044 ...that there's 5 billion bits. 290 00:20:43,247 --> 00:20:47,274 Five billion bits of information in our encyclopedia of life... 291 00:20:47,485 --> 00:20:50,352 ...in the nucleus of every one of our cells. 292 00:20:50,555 --> 00:20:54,116 So if written out in, say, ordinary English... 293 00:20:54,325 --> 00:20:56,953 ...those instructions, that information... 294 00:20:57,161 --> 00:21:01,029 ...would fill 1000 volumes. 295 00:21:01,232 --> 00:21:02,324 Think of it. 296 00:21:02,533 --> 00:21:06,765 In every one of the 100 trillion cells in your body... 297 00:21:06,971 --> 00:21:09,940 ...there's the contents of a complete library of instructions... 298 00:21:10,141 --> 00:21:14,134 ...on how to make every part of you. Those cells are smart. 299 00:21:14,345 --> 00:21:16,836 If this were my gene library... 300 00:21:17,048 --> 00:21:19,949 ...it would contain everything my body knows how to do... 301 00:21:20,151 --> 00:21:21,880 ...without being taught. 302 00:21:22,086 --> 00:21:24,884 The ancient information... 303 00:21:25,089 --> 00:21:29,924 ...is written in exhaustive, careful, redundant detail. 304 00:21:30,127 --> 00:21:33,790 How to laugh, how to sneeze, how to walk... 305 00:21:33,998 --> 00:21:36,398 ...how to recognize patterns, how to reproduce... 306 00:21:36,601 --> 00:21:38,660 ...how to digest an apple. 307 00:21:39,170 --> 00:21:41,832 If written out in the language of chemistry... 308 00:21:42,039 --> 00:21:43,597 ...what would the instructions... 309 00:21:43,808 --> 00:21:46,538 ...for digesting the sugar in an apple look like? 310 00:21:46,744 --> 00:21:48,769 Well, let's see. 311 00:21:49,847 --> 00:21:52,475 Amino acid synthesis, polypeptide chains... 312 00:21:52,683 --> 00:21:57,017 ...transfer RNA, genetic code, enzyme expression... 313 00:21:57,221 --> 00:21:59,781 ...enzyme phosphorylation. We're getting warm. 314 00:21:59,991 --> 00:22:03,859 Hexose monophosphate shunt, citric acid cycle... 315 00:22:04,061 --> 00:22:06,621 Here we are. Anaerobic glycolysis. 316 00:22:06,831 --> 00:22:08,458 Now, eating an apple... 317 00:22:08,666 --> 00:22:11,226 ...may seem like a very simple thing... 318 00:22:11,969 --> 00:22:13,698 ...but it's not. 319 00:22:13,904 --> 00:22:17,806 In fact, if I consciously had to remember and direct... 320 00:22:18,009 --> 00:22:22,343 ...all the chemical steps required to get energy out of food... 321 00:22:22,546 --> 00:22:24,707 ...I'd probably starve to death. 322 00:22:24,915 --> 00:22:29,682 And yet, even a bacterium can do anaerobic glycolysis. 323 00:22:29,887 --> 00:22:34,824 That's why apples rot. It's lunchtime for the bacteria. 324 00:22:35,026 --> 00:22:38,553 They and we and all the creatures in between... 325 00:22:38,763 --> 00:22:42,062 ...possess similar genetic instructions. 326 00:22:42,266 --> 00:22:44,757 Our separate gene libraries... 327 00:22:44,969 --> 00:22:47,699 ...have many pages in common... 328 00:22:47,905 --> 00:22:50,999 ...which is another reminder of the deep interconnection... 329 00:22:51,208 --> 00:22:53,904 ...of all living things on our planet because of... 330 00:22:54,111 --> 00:22:56,136 ...a common evolutionary heritage. 331 00:22:58,983 --> 00:23:01,508 Our present human technology... 332 00:23:01,719 --> 00:23:06,622 ...can duplicate only a tiny fraction of the intricate biochemistry... 333 00:23:06,824 --> 00:23:11,056 ...which our bodies seem to perform so effortlessly. 334 00:23:11,262 --> 00:23:13,822 But we're just beginning the study of biochemistry. 335 00:23:14,031 --> 00:23:18,195 Evolution has had billions of years of practice. 336 00:23:19,170 --> 00:23:21,604 The DNA knows. 337 00:23:22,807 --> 00:23:27,403 Now, what if what we had to do was so complicated... 338 00:23:27,611 --> 00:23:31,638 ...that even several billion bits of information wasn't enough? 339 00:23:31,849 --> 00:23:35,341 What if, for example, the environment were changing so fast... 340 00:23:35,553 --> 00:23:39,011 ...that the pre-coded genetic encyclopedia... 341 00:23:39,223 --> 00:23:42,681 ...which may have served us perfectly well in the past is now... 342 00:23:42,893 --> 00:23:45,987 ...not perfectly adequate? 343 00:23:46,197 --> 00:23:47,755 Why, then... 344 00:23:47,965 --> 00:23:52,231 ...even a gene library of 1000 volumes wouldn't be enough. 345 00:23:52,436 --> 00:23:55,633 That's why we have brains. 346 00:23:59,110 --> 00:24:01,374 Like our other organs, the brain has evolved... 347 00:24:01,579 --> 00:24:04,047 ...increasing over millions of years... 348 00:24:04,248 --> 00:24:07,240 ...in complexity and information content. 349 00:24:07,451 --> 00:24:11,888 Its structure reflects all the stages through which it has passed. 350 00:24:12,323 --> 00:24:17,022 The brain has evolved from the inside out. 351 00:24:17,228 --> 00:24:20,857 Deep inside is the oldest part, the so-called brain stem. 352 00:24:21,465 --> 00:24:24,093 It conducts many of the basic biological functions... 353 00:24:24,301 --> 00:24:26,735 ...including the rhythms of life... 354 00:24:26,937 --> 00:24:29,770 ...like heartbeat and respiration. 355 00:24:29,974 --> 00:24:32,943 The higher functions of the brain have evolved... 356 00:24:33,144 --> 00:24:36,705 ...in three successive stages according to a provocative insight... 357 00:24:36,914 --> 00:24:39,747 ...by the American biologist Paul MacLean. 358 00:24:39,950 --> 00:24:44,284 You see, capping the brain stem is the so-called R-complex... 359 00:24:44,488 --> 00:24:46,251 "R" for reptile. 360 00:24:46,457 --> 00:24:48,186 It's the seat of... 361 00:24:48,425 --> 00:24:51,622 ...aggression, ritual, territoriality... 362 00:24:51,829 --> 00:24:53,694 ...and social hierarchies. 363 00:24:53,898 --> 00:24:57,061 It evolved some hundreds of millions of years ago... 364 00:24:57,268 --> 00:24:59,566 ...in our reptilian ancestors. 365 00:24:59,770 --> 00:25:04,537 So, deep inside our brains is something rather like... 366 00:25:04,742 --> 00:25:07,040 ...the brain of a crocodile. 367 00:25:07,244 --> 00:25:10,907 Surrounding the R-complex is the limbic system... 368 00:25:11,115 --> 00:25:12,343 ...or mammal brain. 369 00:25:12,550 --> 00:25:14,848 It evolved some tens of millions of years ago... 370 00:25:15,286 --> 00:25:17,777 ...in ancestors who were mammals all right... 371 00:25:17,988 --> 00:25:22,425 ...but not yet primates like monkeys or apes. 372 00:25:22,626 --> 00:25:26,187 It's a major source of our moods and emotions... 373 00:25:26,397 --> 00:25:29,696 ...our concern and care for the young. 374 00:25:29,900 --> 00:25:33,734 And then, finally, on the outside of the brain... 375 00:25:34,338 --> 00:25:37,398 ...living in a kind of uneasy truce with... 376 00:25:37,608 --> 00:25:41,305 ...the more primitive brains beneath, is the cerebral cortex... 377 00:25:41,512 --> 00:25:43,912 ...evolved millions of years ago... 378 00:25:44,114 --> 00:25:46,605 ...in ancestors who were primates. 379 00:25:59,930 --> 00:26:02,398 This is the point of embarkation... 380 00:26:02,600 --> 00:26:04,693 ...for all our cosmic journeys. 381 00:26:04,902 --> 00:26:06,597 The cerebral cortex... 382 00:26:06,804 --> 00:26:10,001 ...where matter is transformed into consciousness. 383 00:26:10,207 --> 00:26:14,507 Here, comprising more than two-thirds of the brain mass... 384 00:26:14,712 --> 00:26:18,512 ...is the realm both of intuition and of critical analysis. 385 00:26:18,716 --> 00:26:21,913 It's here that we have ideas and inspirations. 386 00:26:22,119 --> 00:26:23,882 Here that we read and write. 387 00:26:24,088 --> 00:26:27,421 Here that we do mathematics and music. 388 00:26:27,625 --> 00:26:31,322 The cortex regulates our conscious lives. 389 00:26:31,528 --> 00:26:34,463 It is the distinction of our species... 390 00:26:34,665 --> 00:26:36,656 ...the seat of our humanity. 391 00:26:36,867 --> 00:26:39,131 Art and science live here. 392 00:26:39,336 --> 00:26:43,238 Civilization is a product of the cerebral cortex. 393 00:26:45,843 --> 00:26:46,969 Behind the forehead... 394 00:26:47,177 --> 00:26:50,112 ...are the frontal lobes of the cerebral cortex. 395 00:26:50,314 --> 00:26:52,874 They may be where we anticipate events... 396 00:26:53,083 --> 00:26:55,313 ...where we figure out the future. 397 00:26:55,519 --> 00:26:57,749 But if we can foresee an unpleasant future... 398 00:26:57,955 --> 00:26:59,889 ...we can take steps to avoid it. 399 00:27:00,090 --> 00:27:02,115 Down here in the frontal lobes... 400 00:27:02,326 --> 00:27:04,886 ...may be the means of ensuring human survival... 401 00:27:05,095 --> 00:27:07,825 ...if we have the wisdom to pay attention. 402 00:27:10,768 --> 00:27:15,205 Inside the cerebral cortex is the microscopic structure of thought. 403 00:27:15,406 --> 00:27:19,001 The language of the brain is not the DNA language of the genes. 404 00:27:19,209 --> 00:27:22,736 What we know is encoded in cells called neurons... 405 00:27:22,947 --> 00:27:24,278 ...tiny switching elements... 406 00:27:24,481 --> 00:27:28,281 ...every connection representing one bit of information. 407 00:27:28,485 --> 00:27:31,682 How many neurons do each of us have? Maybe 100 billion. 408 00:27:31,889 --> 00:27:35,188 Comparable to the number of stars in the Milky Way galaxy. 409 00:27:35,392 --> 00:27:39,920 And there are something like 100 trillion neural connections. 410 00:27:41,999 --> 00:27:46,333 This intricate and marvelous network of neurons... 411 00:27:46,537 --> 00:27:50,303 ...has been called an enchanted loom... 412 00:27:50,507 --> 00:27:53,305 ...where millions of flashing shuttles... 413 00:27:53,510 --> 00:27:56,206 ...weave a dissolving pattern. 414 00:27:56,413 --> 00:27:59,974 Even in sleep, the brain is pulsing and throbbing and flashing... 415 00:28:00,184 --> 00:28:03,085 ...with the complex business of human life: 416 00:28:03,287 --> 00:28:06,313 Dreaming, remembering, figuring things out. 417 00:28:06,523 --> 00:28:09,651 Our thoughts, our visions, our fantasies... 418 00:28:09,860 --> 00:28:12,852 ...have a tangible, physical reality. 419 00:28:13,063 --> 00:28:14,860 What does a thought look like? 420 00:28:15,065 --> 00:28:19,001 Well, it's made of hundreds of electrochemical impulses. 421 00:28:19,803 --> 00:28:21,464 Over there, for example, is... 422 00:28:21,672 --> 00:28:23,071 ...a spark of a memory. 423 00:28:23,273 --> 00:28:24,535 Maybe... 424 00:28:24,742 --> 00:28:28,701 ...the smell of lilacs on a country road in childhood. 425 00:28:28,912 --> 00:28:33,246 And there goes a bit of an anxious all points bulletin. 426 00:28:33,450 --> 00:28:36,942 Perhaps, "Where did I leave my keys?" 427 00:28:39,656 --> 00:28:42,784 The neurons store sounds too... 428 00:28:42,993 --> 00:28:44,790 ...and snatches of music. 429 00:28:44,995 --> 00:28:49,329 Whole orchestras play inside our heads. 430 00:28:54,738 --> 00:28:59,004 The landscape of the human cerebral cortex is deeply furrowed. 431 00:28:59,209 --> 00:29:00,642 There's a good reason for it. 432 00:29:00,844 --> 00:29:02,334 These convolutions... 433 00:29:02,546 --> 00:29:06,539 ...greatly increase the surface area available for information storage... 434 00:29:06,750 --> 00:29:10,049 ...in a skull of limited size. 435 00:29:14,391 --> 00:29:17,554 The world of thought is divided into two hemispheres. 436 00:29:17,761 --> 00:29:20,491 Over there is the right hemisphere of the cerebral cortex. 437 00:29:20,697 --> 00:29:23,359 It's mainly responsible for pattern recognition... 438 00:29:23,567 --> 00:29:26,661 ...intuition, sensitivity, creative insights. 439 00:29:26,870 --> 00:29:29,065 And over here is the left hemisphere... 440 00:29:29,273 --> 00:29:33,437 ...presiding over rational, analytic and critical thinking. 441 00:29:39,016 --> 00:29:42,110 These are the two sides... 442 00:29:42,319 --> 00:29:46,346 ...the dual strengths, the essential opposites... 443 00:29:46,557 --> 00:29:48,525 ...that characterize human thinking. 444 00:29:48,725 --> 00:29:51,285 Before us are the means... 445 00:29:51,495 --> 00:29:55,556 ...both for generating ideas and for testing their validity. 446 00:29:55,766 --> 00:30:00,066 There's a continuous dialogue between the two hemispheres of the brain... 447 00:30:00,270 --> 00:30:04,639 ...channeled through this immense bundle of nerve fibers... 448 00:30:04,842 --> 00:30:07,606 ...which is called the corpus callosum. 449 00:30:07,811 --> 00:30:12,145 It's a bridge between creativity and analysis... 450 00:30:12,349 --> 00:30:16,410 ...both of which are necessary if we are to understand the world. 451 00:30:17,955 --> 00:30:21,857 The information content of the human brain expressed in bits... 452 00:30:22,059 --> 00:30:24,425 ...is comparable to the number of connections between... 453 00:30:24,628 --> 00:30:26,095 ...the neurons in the cortex... 454 00:30:26,296 --> 00:30:28,196 ...about 100 trillion bits... 455 00:30:28,398 --> 00:30:31,196 ...10 to the 14th connections. 456 00:30:31,401 --> 00:30:34,859 If written out in English, it would fill 20 million volumes... 457 00:30:35,072 --> 00:30:37,540 ...as many as in the world's largest libraries. 458 00:30:37,741 --> 00:30:41,302 The equivalent of 20 million volumes worth of information... 459 00:30:41,512 --> 00:30:43,878 ...is inside the heads of every one of us. 460 00:30:44,081 --> 00:30:48,814 The brain is a very big place in a very small space. 461 00:30:50,888 --> 00:30:55,348 Most of the books in the brain are up here in the cerebral cortex. 462 00:30:55,559 --> 00:30:58,460 Down there, in the basement of the brain... 463 00:30:58,662 --> 00:31:00,687 ...are the functions that our ancestors... 464 00:31:00,898 --> 00:31:02,889 ...mainly depended on for survival: 465 00:31:03,100 --> 00:31:06,092 Aggression, child rearing, sex... 466 00:31:06,303 --> 00:31:08,794 ...the willingness to follow leaders blindly. 467 00:31:09,006 --> 00:31:12,407 Lots of things that we can still recognize in our lives today. 468 00:31:12,609 --> 00:31:14,702 Of the higher brain functions... 469 00:31:14,912 --> 00:31:16,539 ...some of them, like... 470 00:31:16,747 --> 00:31:18,772 ...reading, writing, speaking... 471 00:31:18,982 --> 00:31:23,885 ...seem to be located in particular places in the cerebral cortex. 472 00:31:24,087 --> 00:31:26,282 On the other hand, each memory... 473 00:31:26,490 --> 00:31:30,893 ...seems to be stored in many separate locales in the brain. 474 00:31:31,094 --> 00:31:33,790 Old memories are in lots of places. 475 00:31:40,671 --> 00:31:42,502 Here is one of my earliest memories. 476 00:31:51,848 --> 00:31:53,110 That's a good boy. 477 00:31:53,317 --> 00:31:55,649 Lunch is almost ready. 478 00:32:18,942 --> 00:32:21,137 That was a long time ago. 479 00:32:23,146 --> 00:32:25,842 But its imprint has not faded... 480 00:32:26,049 --> 00:32:29,018 ...in the library of this brain. 481 00:32:36,560 --> 00:32:39,893 But the brain does much more than just recollect. 482 00:32:40,097 --> 00:32:41,325 It inter-compares. 483 00:32:41,531 --> 00:32:43,931 It synthesizes. It analyzes. 484 00:32:44,134 --> 00:32:46,602 It generates abstractions. 485 00:32:51,742 --> 00:32:54,472 The simplest thought, like the concept of the number one... 486 00:32:54,678 --> 00:32:56,976 ...has an elaborate, logical underpinning. 487 00:32:57,180 --> 00:32:58,841 The brain has its own language... 488 00:32:59,049 --> 00:33:01,916 ...for testing the world's structure and consistency. 489 00:33:02,119 --> 00:33:04,679 But we never see the machinery of logical analysis... 490 00:33:04,888 --> 00:33:06,719 ...only the conclusions. 491 00:33:08,625 --> 00:33:11,355 There is so much more that we must figure out... 492 00:33:11,561 --> 00:33:13,222 ...than the genes can know. 493 00:33:13,430 --> 00:33:15,864 That's why the brain library... 494 00:33:16,066 --> 00:33:19,502 ...has 10,000 times more information in it... 495 00:33:19,703 --> 00:33:21,136 ...than the gene library. 496 00:33:21,338 --> 00:33:26,037 Our passion for learning is the tool for our survival. 497 00:33:31,315 --> 00:33:35,251 And unlike the musty bindings of our gene library... 498 00:33:35,452 --> 00:33:37,886 ...in which hardly a word changes in a century... 499 00:33:38,088 --> 00:33:41,751 ...the brain library is made of loose-leaf books. 500 00:33:41,958 --> 00:33:45,917 We're constantly adding new pages and new volumes. 501 00:33:54,004 --> 00:33:57,667 Emotions and ritual behavior patterns... 502 00:33:57,874 --> 00:33:59,671 ...are built very deeply into us. 503 00:33:59,876 --> 00:34:02,777 They're part of our humanity. 504 00:34:02,979 --> 00:34:05,539 But they're not characteristically human. 505 00:34:05,749 --> 00:34:07,740 Many other animals have feelings. 506 00:34:07,951 --> 00:34:11,580 What distinguishes our species is thought. 507 00:34:11,788 --> 00:34:16,657 The cerebral cortex is, in a way, a liberation. 508 00:34:16,860 --> 00:34:18,987 We need no longer be trapped... 509 00:34:19,196 --> 00:34:22,222 ...in the genetically inherited behavior patterns... 510 00:34:22,432 --> 00:34:24,764 ...of lizards and baboons: 511 00:34:24,968 --> 00:34:27,596 Territoriality and aggression... 512 00:34:27,804 --> 00:34:30,204 ...and dominance hierarchies. 513 00:34:30,407 --> 00:34:31,874 We are, each of us... 514 00:34:32,075 --> 00:34:35,602 ...largely responsible for what gets put into our brains... 515 00:34:35,812 --> 00:34:40,010 ...for what, as adults, we wind up caring for... 516 00:34:40,217 --> 00:34:41,809 ...and knowing about. 517 00:34:42,018 --> 00:34:45,044 No longer at the mercy of the reptile brain... 518 00:34:45,255 --> 00:34:48,656 ...we can change ourselves. 519 00:34:48,859 --> 00:34:51,123 Think of the possibilities. 520 00:35:22,759 --> 00:35:24,750 The city, like the brain... 521 00:35:24,961 --> 00:35:27,429 ...has evolved in successive stages. 522 00:35:27,631 --> 00:35:30,429 The vestiges of its past are still retained... 523 00:35:30,634 --> 00:35:33,933 ...among the constructions of the present. 524 00:35:42,245 --> 00:35:45,078 A city like New York developed from a small center... 525 00:35:45,282 --> 00:35:49,218 ...and slowly grew leaving many of the old parts still functioning. 526 00:35:49,419 --> 00:35:52,388 Some of the major streets date to the 17th century. 527 00:35:52,589 --> 00:35:55,217 Its commercial hub, to the 18th century. 528 00:35:55,425 --> 00:35:57,791 The water and gas works, to the 19th. 529 00:35:57,994 --> 00:36:02,294 The electrical and communications systems, to the 20th century. 530 00:36:12,642 --> 00:36:15,634 The city has evolved much faster than the brain. 531 00:36:15,846 --> 00:36:17,711 Only 10,000 years ago... 532 00:36:17,914 --> 00:36:20,144 ...the human brain looked exactly as it does today... 533 00:36:20,350 --> 00:36:21,817 ...and we were just as smart. 534 00:36:22,018 --> 00:36:23,417 But there were no cities... 535 00:36:23,620 --> 00:36:28,421 ...only a few scattered encampments in the vast primordial forests. 536 00:36:28,625 --> 00:36:30,422 Today, it's just the opposite. 537 00:36:30,627 --> 00:36:35,564 Forests and grasslands often seem like scattered islands in a sea of cities. 538 00:36:37,200 --> 00:36:39,327 If you were an observer from an alien world... 539 00:36:39,536 --> 00:36:41,697 ...you would've noticed that something complicated... 540 00:36:41,905 --> 00:36:44,897 ...has been happening over the last few thousand years. 541 00:36:45,108 --> 00:36:47,975 It might take you a while to figure out the details... 542 00:36:48,178 --> 00:36:50,578 ...but you would recognize by its complexity... 543 00:36:50,780 --> 00:36:53,578 ...unmistakable evidence for intelligent life. 544 00:36:54,584 --> 00:36:56,643 On closer scrutiny, you might recognize... 545 00:36:56,853 --> 00:36:58,582 ...individual, intelligent beings. 546 00:37:04,728 --> 00:37:08,425 The evolution of the city is due to their conscious activity. 547 00:37:09,032 --> 00:37:12,490 Millions of human beings working, more or less, together... 548 00:37:12,702 --> 00:37:15,466 ...to preserve the city, to reconstruct it... 549 00:37:15,672 --> 00:37:17,162 ...and to change it. 550 00:37:30,754 --> 00:37:33,723 It might be more efficient if all civic systems... 551 00:37:33,924 --> 00:37:36,688 ...were periodically replaced from top to bottom. 552 00:37:36,893 --> 00:37:38,588 But, as in the brain... 553 00:37:38,795 --> 00:37:41,628 ...everything has to work during the renovation. 554 00:37:41,831 --> 00:37:43,731 So the city mostly adds new parts... 555 00:37:43,934 --> 00:37:47,665 ...while the old parts continue, more or less, to function. 556 00:37:50,874 --> 00:37:53,035 For example, in the 17th century... 557 00:37:53,243 --> 00:37:55,404 ...you traveled between Brooklyn and Manhattan... 558 00:37:55,612 --> 00:37:57,842 ...across the East River by ferry. 559 00:37:58,048 --> 00:38:01,575 In the 19th century, the technology became available to construct... 560 00:38:01,785 --> 00:38:03,582 ...a suspension bridge across the river. 561 00:38:03,787 --> 00:38:06,813 It was built precisely at the site of the ferry terminal... 562 00:38:07,023 --> 00:38:10,720 ...because major thoroughfares were already converging there. 563 00:38:11,962 --> 00:38:15,090 When it was possible to construct a tunnel under the river... 564 00:38:15,298 --> 00:38:19,598 ...that, too, was built in the same place and for the same reason. 565 00:38:19,803 --> 00:38:23,569 This use and restructuring of previous systems for new purposes... 566 00:38:23,773 --> 00:38:27,174 ...is very much like the pattern of biological evolution. 567 00:38:27,377 --> 00:38:29,811 Or consider Third Avenue. 568 00:38:30,013 --> 00:38:31,503 In the 17th century... 569 00:38:31,715 --> 00:38:35,583 ...you made your way uptown on foot or on horseback. 570 00:38:36,086 --> 00:38:38,816 A little later, there were coaches... 571 00:38:39,022 --> 00:38:42,423 ...the horses prancing, the coachmen cracking their whips. 572 00:38:43,026 --> 00:38:46,689 And then these were replaced by horse-drawn trolleys... 573 00:38:46,896 --> 00:38:50,263 ...clanging along fixed tracks on this avenue. 574 00:38:50,467 --> 00:38:52,958 Then electrical technology developed... 575 00:38:53,169 --> 00:38:56,798 ...and a great elevated railway line was constructed... 576 00:38:57,774 --> 00:39:01,574 ...called the Third Avenue El, which dominated the street... 577 00:39:01,778 --> 00:39:06,147 ...until 1954, when it was utterly demolished. 578 00:39:06,349 --> 00:39:11,286 Anyway, the El was then replaced by buses and taxicabs... 579 00:39:11,554 --> 00:39:13,784 ...which still are the main forms... 580 00:39:13,990 --> 00:39:16,220 ...of public transportation on Third Avenue. 581 00:39:17,027 --> 00:39:20,121 Now as gasoline becomes a rare commodity... 582 00:39:20,330 --> 00:39:23,857 ...the combustion engine will be replaced by something else. 583 00:39:24,067 --> 00:39:29,004 Maybe public transport on Third Avenue in the 21st century... 584 00:39:29,539 --> 00:39:34,272 ...will be by, I don't know, pneumatic tubes or electric cars. 585 00:39:35,078 --> 00:39:39,344 Every step in the evolution of Third Avenue transport... 586 00:39:39,549 --> 00:39:41,744 ...has been conservative... 587 00:39:41,951 --> 00:39:44,112 ...following a route first laid down... 588 00:39:44,320 --> 00:39:46,083 ...in the 17th century. 589 00:39:46,289 --> 00:39:50,385 But the brain is still more conservative than the city. 590 00:39:50,627 --> 00:39:54,427 If this were the brain, we might have horse-drawn trolleys... 591 00:39:54,631 --> 00:39:56,326 ...and the El and buses... 592 00:39:56,533 --> 00:39:59,024 ...all operating simultaneously... 593 00:39:59,235 --> 00:40:01,760 ...redundantly, competitively. 594 00:40:01,971 --> 00:40:04,838 The vestiges of earlier history clearly in evidence. 595 00:40:15,919 --> 00:40:18,353 When our genes could not store... 596 00:40:18,555 --> 00:40:21,285 ...all the information necessary for our survival... 597 00:40:21,491 --> 00:40:24,654 ...we slowly invented brains. 598 00:40:25,395 --> 00:40:30,025 But then the time came, maybe tens of thousands of years ago... 599 00:40:30,300 --> 00:40:32,427 ...when we needed to know more than... 600 00:40:32,635 --> 00:40:35,035 ...could conveniently be stored in brains. 601 00:40:38,808 --> 00:40:43,040 So we learned to stockpile enormous quantities of information... 602 00:40:43,246 --> 00:40:44,736 ...outside our bodies. 603 00:40:44,948 --> 00:40:47,917 We are the only species on Earth, so far as we know... 604 00:40:48,118 --> 00:40:51,144 ...to have invented a communal memory. 605 00:40:51,354 --> 00:40:54,949 The warehouse of that memory is called the library. 606 00:40:57,660 --> 00:40:59,491 Libraries also have evolved. 607 00:40:59,696 --> 00:41:01,891 The Assyrian library of Ashurbanipal... 608 00:41:02,098 --> 00:41:04,430 ...had thousands of clay tablets. 609 00:41:04,634 --> 00:41:07,535 The celebrated Library of Alexandria in Egypt... 610 00:41:07,737 --> 00:41:10,865 ...consisted of almost a million papyrus scrolls. 611 00:41:11,074 --> 00:41:14,373 Great modern libraries, like the New York Public Library... 612 00:41:14,577 --> 00:41:17,569 ...contain some 10 million books. 613 00:41:20,617 --> 00:41:25,054 That's more than 10 to the 14th bits of information in words. 614 00:41:25,255 --> 00:41:29,282 More than 100 trillion bits, and if we count pictures... 615 00:41:29,492 --> 00:41:33,519 ...it's something like 10 to the 15th bits of information. 616 00:41:33,730 --> 00:41:35,891 Now, that's more than 10,000 times... 617 00:41:36,099 --> 00:41:39,159 ...the total number of bits of information in our genes. 618 00:41:39,369 --> 00:41:40,927 Something like 10 times... 619 00:41:41,137 --> 00:41:44,538 ...the total amount of information in our brains. 620 00:41:44,741 --> 00:41:47,403 If I were to read a book a week... 621 00:41:47,610 --> 00:41:50,306 ...for my entire adult lifetime... 622 00:41:50,513 --> 00:41:52,481 ...and I lived an ordinary lifetime... 623 00:41:52,682 --> 00:41:53,910 ...when I was all done... 624 00:41:54,117 --> 00:41:57,609 ...I would've read maybe a few thousand books. 625 00:41:57,821 --> 00:41:59,083 No more. 626 00:41:59,289 --> 00:42:03,953 In this library, that's from about here... 627 00:42:09,265 --> 00:42:10,698 ...roughly... 628 00:42:12,402 --> 00:42:14,893 ...to about here. 629 00:42:15,104 --> 00:42:18,164 But that's only a 10th of a percent or so... 630 00:42:18,374 --> 00:42:21,070 ...of the total number of books in the library. 631 00:42:21,277 --> 00:42:25,407 The trick is to know which books to read. 632 00:42:27,283 --> 00:42:29,843 But they're all here. 633 00:42:39,162 --> 00:42:43,189 What an astonishing thing a book is. 634 00:42:43,399 --> 00:42:46,891 It's a flat object made from a tree... 635 00:42:47,103 --> 00:42:51,540 ...with flexible parts on which are imprinted... 636 00:42:51,741 --> 00:42:54,676 ...lots of funny dark squiggles. 637 00:42:54,878 --> 00:42:57,108 But one glance at it... 638 00:42:57,313 --> 00:43:00,146 ...and you're inside the mind of another person. 639 00:43:00,350 --> 00:43:04,081 Maybe somebody dead for thousands of years. 640 00:43:04,287 --> 00:43:06,255 Across the millennia... 641 00:43:06,456 --> 00:43:09,983 ...an author is speaking clearly and silently... 642 00:43:10,193 --> 00:43:13,094 ...inside your head, directly to you. 643 00:43:13,296 --> 00:43:17,289 Writing is perhaps the greatest of human inventions. 644 00:43:17,500 --> 00:43:20,435 Binding together people who never knew each other. 645 00:43:20,637 --> 00:43:23,401 Citizens of distant epochs. 646 00:43:23,606 --> 00:43:26,973 Books break the shackles of time. 647 00:43:27,176 --> 00:43:32,113 A book is proof that humans are capable of working magic. 648 00:43:32,382 --> 00:43:35,715 And this room is filled with magic. 649 00:43:37,921 --> 00:43:40,981 Some of the earliest authors wrote on... 650 00:43:41,624 --> 00:43:44,650 ...bones and stones. 651 00:43:44,861 --> 00:43:49,161 Cuneiform writing is the remote ancestor of the Western alphabet. 652 00:43:49,365 --> 00:43:53,267 It was invented in the Near East about 5000 years ago. 653 00:43:53,469 --> 00:43:55,096 Its purpose? 654 00:43:55,305 --> 00:43:56,397 To keep records. 655 00:43:56,606 --> 00:44:00,303 Records of the purchase of grain, the sale of land... 656 00:44:00,510 --> 00:44:04,310 ...the triumphs of kings, the statutes of priests... 657 00:44:04,514 --> 00:44:06,675 ...the positions of the stars... 658 00:44:06,883 --> 00:44:09,681 ...the prayers to the gods. 659 00:44:09,886 --> 00:44:12,650 This cone was made... 660 00:44:12,855 --> 00:44:15,346 ...around the year 2350 B.C. 661 00:44:15,558 --> 00:44:19,688 4300 years ago, there were people chipping and chiseling away... 662 00:44:19,896 --> 00:44:21,454 ...the message on this cone. 663 00:44:21,664 --> 00:44:23,461 What is that message? 664 00:44:23,666 --> 00:44:25,463 It's a prayer. 665 00:44:25,668 --> 00:44:29,126 The inscription on this cylinder... 666 00:44:30,139 --> 00:44:32,403 ...honors a king. 667 00:44:32,942 --> 00:44:37,276 Nebuchadnezzar, king of Babylon, in the 6th century B.C. 668 00:44:37,480 --> 00:44:41,143 For thousands of years, writing was chiseled into stone... 669 00:44:41,351 --> 00:44:45,378 ...scratched onto wax or bark or leather... 670 00:44:45,588 --> 00:44:49,490 ...painted on bamboo or silk or paper... 671 00:44:49,692 --> 00:44:52,889 ...but always in editions of one copy. 672 00:44:53,096 --> 00:44:54,927 One copy at a time... 673 00:44:55,131 --> 00:44:58,726 ...always, except for inscriptions on monuments... 674 00:44:58,935 --> 00:45:00,994 ...for a tiny readership. 675 00:45:14,083 --> 00:45:17,382 But then in China... 676 00:45:17,587 --> 00:45:20,317 ...between the 2nd and the 6th centuries... 677 00:45:20,523 --> 00:45:24,482 ...paper, ink and printing with carved wooden blocks... 678 00:45:24,694 --> 00:45:27,288 ...were all invented, more or less, together... 679 00:45:27,497 --> 00:45:32,434 ...permitting many copies of a work to be made and distributed. 680 00:45:32,702 --> 00:45:35,899 This is Chinese magic... 681 00:45:36,105 --> 00:45:38,130 ...from the 12th century. 682 00:45:39,642 --> 00:45:42,076 It took 1000 years for the idea to catch on... 683 00:45:42,278 --> 00:45:45,406 ...in relatively remote and backward Europe. 684 00:45:45,615 --> 00:45:49,483 Just before the invention of movable type... 685 00:45:49,752 --> 00:45:52,016 ...around the year 1450... 686 00:45:52,221 --> 00:45:55,019 ...there were only a few tens of thousands of books in Europe. 687 00:45:55,224 --> 00:45:57,784 Every one of them handwritten. 688 00:45:57,994 --> 00:46:02,829 Fifty years later, there were 10 million printed books in Europe. 689 00:46:03,032 --> 00:46:07,298 Learning became available to anyone who could read. 690 00:46:07,503 --> 00:46:10,734 Suddenly, books were being printed all over the world. 691 00:46:10,940 --> 00:46:13,966 Magic was everywhere. 692 00:46:15,778 --> 00:46:17,541 It is 23 centuries... 693 00:46:17,747 --> 00:46:20,147 ...since the founding of the Alexandrian library. 694 00:46:20,683 --> 00:46:24,517 Since then, 100 generations have lived and died. 695 00:46:24,720 --> 00:46:27,553 If information were passed on merely by word of mouth... 696 00:46:27,757 --> 00:46:29,816 ...how little we should know of our own past... 697 00:46:30,026 --> 00:46:32,392 ...how slow would be our progress. 698 00:46:32,595 --> 00:46:34,825 Everything would depend on what we'd been told... 699 00:46:35,031 --> 00:46:36,623 ...on how accurate the account. 700 00:46:36,833 --> 00:46:38,630 Ancient learning might be revered... 701 00:46:38,835 --> 00:46:41,929 ...but in successive retellings, it would become muddled... 702 00:46:42,138 --> 00:46:43,537 ...and then lost. 703 00:46:43,739 --> 00:46:46,674 Books permit us to voyage through time... 704 00:46:46,876 --> 00:46:49,868 ...to tap the wisdom of our ancestors. 705 00:46:51,581 --> 00:46:54,948 A library connects us with the insights and knowledge... 706 00:46:55,151 --> 00:46:57,881 ...of the greatest minds and the best teachers... 707 00:46:58,087 --> 00:47:01,113 ...drawn from the whole planet and from all our history... 708 00:47:01,324 --> 00:47:03,554 ...to instruct us without tiring... 709 00:47:03,759 --> 00:47:06,592 ...and to inspire us to make our own contributions... 710 00:47:06,796 --> 00:47:10,459 ...to the collective knowledge of the human species. 711 00:47:18,541 --> 00:47:22,341 There's a fair number of Gutenberg Bibles... 712 00:47:22,545 --> 00:47:25,412 ...and first folios of Shakespeare in the world... 713 00:47:25,615 --> 00:47:27,947 ...but most of the books you see here... 714 00:47:28,151 --> 00:47:32,520 ...are limited editions with very few surviving copies. 715 00:47:32,722 --> 00:47:34,713 But there also exists in the world... 716 00:47:34,924 --> 00:47:38,291 ...mass printings of paperbound books... 717 00:47:38,494 --> 00:47:42,089 ...that I think are still more wonderful. 718 00:47:42,298 --> 00:47:44,698 For the price of a modest meal... 719 00:47:44,901 --> 00:47:47,631 ...you get the history of Rome. 720 00:47:48,271 --> 00:47:52,207 Books are like seeds: They can lie dormant for centuries... 721 00:47:52,408 --> 00:47:57,072 ...but they may also produce flowers in the most unpromising soil. 722 00:47:57,280 --> 00:48:02,217 These books are the repositories of the knowledge of our species... 723 00:48:02,485 --> 00:48:05,648 ...and of our long evolutionary journey... 724 00:48:05,855 --> 00:48:09,518 ...from genes to brains to books. 725 00:48:27,877 --> 00:48:29,469 Libraries in ancient Egypt... 726 00:48:29,679 --> 00:48:31,647 ...bore these words on their walls: 727 00:48:32,415 --> 00:48:35,748 "Nourishment for the soul." 728 00:48:36,118 --> 00:48:40,680 And that's still a pretty fair assessment of what libraries provide. 729 00:48:57,707 --> 00:49:00,870 Even at night, the city, like the brain... 730 00:49:01,077 --> 00:49:03,841 ...is busy assimilating and distributing information. 731 00:49:04,046 --> 00:49:05,809 Information keeps it alive... 732 00:49:06,015 --> 00:49:10,213 ...and provides the tools to adapt to changing conditions. 733 00:49:12,288 --> 00:49:13,550 The long human journey... 734 00:49:13,756 --> 00:49:18,022 ...from genes to brains to books continues. 735 00:49:22,131 --> 00:49:23,928 Information itself evolves... 736 00:49:24,133 --> 00:49:28,433 ...nurtured by open communication and free inquiry. 737 00:49:31,641 --> 00:49:33,836 The units of biological evolution are genes. 738 00:49:34,243 --> 00:49:36,939 The units of cultural evolution are ideas. 739 00:49:37,146 --> 00:49:39,444 Ideas are transported all over the planet. 740 00:49:39,715 --> 00:49:41,342 They reproduce through communication. 741 00:49:41,684 --> 00:49:44,915 They are selected by analysis and debate. 742 00:49:45,121 --> 00:49:49,217 In the last few millennia, something extraordinary has happened on Earth. 743 00:49:49,959 --> 00:49:53,292 Rich information from distant lands and peoples... 744 00:49:53,496 --> 00:49:55,987 ...has become routinely available. 745 00:49:57,433 --> 00:49:59,594 The number of bits to which we have access... 746 00:49:59,802 --> 00:50:01,895 ...has grown dramatically. 747 00:50:06,776 --> 00:50:09,210 Computers can now store and process... 748 00:50:09,412 --> 00:50:12,438 ...enormous amounts of information extremely rapidly. 749 00:50:12,648 --> 00:50:15,412 In our time, a revolution has begun. 750 00:50:15,618 --> 00:50:17,518 A revolution perhaps as significant... 751 00:50:17,720 --> 00:50:20,382 ...as the evolution of DNA and nervous systems... 752 00:50:20,589 --> 00:50:22,079 ...and the invention of writing. 753 00:50:23,225 --> 00:50:26,592 Direct communication among billions of human beings... 754 00:50:26,796 --> 00:50:29,993 ...is now made possible by computers and satellites. 755 00:50:30,666 --> 00:50:33,601 The potential for a global intelligence is emerging. 756 00:50:33,803 --> 00:50:38,001 Linking all the brains on Earth into a planetary consciousness. 757 00:50:41,811 --> 00:50:43,870 Elsewhere, there may be brains... 758 00:50:44,080 --> 00:50:45,877 ...even planetary brains... 759 00:50:46,082 --> 00:50:48,516 ...but there will be no brains quite like ours. 760 00:50:48,718 --> 00:50:52,552 Mutation and natural selection are basically random processes. 761 00:50:52,755 --> 00:50:54,620 If the Earth were started over again... 762 00:50:54,824 --> 00:50:56,758 ...intelligence might very well emerge... 763 00:50:56,959 --> 00:51:01,328 ...but anything closely resembling a human being would be unlikely. 764 00:51:02,698 --> 00:51:07,067 On another planet with a different sequence of random processes... 765 00:51:07,269 --> 00:51:08,964 ...to make heredity diversity... 766 00:51:09,171 --> 00:51:11,366 ...and a different environment... 767 00:51:11,574 --> 00:51:13,906 ...to select particular combinations of genes... 768 00:51:14,110 --> 00:51:16,840 ...the chance of finding beings very similar to us... 769 00:51:17,046 --> 00:51:18,513 ...must be close to zero. 770 00:51:19,081 --> 00:51:21,140 But the chance of finding another form of intelligence... 771 00:51:21,350 --> 00:51:22,442 ...isn't close to zero. 772 00:51:22,651 --> 00:51:26,781 Their brains may well have evolved from the inside out as ours have. 773 00:51:26,989 --> 00:51:30,789 They may well have switching elements analogous to our neurons... 774 00:51:30,993 --> 00:51:33,188 ...but their neurons might be different. 775 00:51:33,396 --> 00:51:37,059 Maybe they're superconductors which work at very low temperatures... 776 00:51:37,266 --> 00:51:40,064 ...in which case, their speed of thought... 777 00:51:40,269 --> 00:51:43,170 ...might be 10 million times faster than ours. 778 00:51:43,906 --> 00:51:46,807 Or perhaps their neurons are not in... 779 00:51:47,009 --> 00:51:49,876 ...direct physical contact with each other... 780 00:51:50,079 --> 00:51:52,411 ...but in radio communication. 781 00:51:52,615 --> 00:51:54,378 So a single intelligent being... 782 00:51:54,583 --> 00:51:57,950 ...could be distributed among many different organisms. 783 00:51:58,154 --> 00:52:01,146 There may be planets in which intelligent beings have... 784 00:52:01,357 --> 00:52:05,521 ...not 10 to the 11th neurons each, as we do... 785 00:52:05,728 --> 00:52:08,993 ...but 10 to the 20th or 10 to the 30th. 786 00:52:09,698 --> 00:52:13,031 I wonder what they would know. 787 00:52:13,235 --> 00:52:14,862 If we could make contact... 788 00:52:15,070 --> 00:52:16,162 ...there would be... 789 00:52:16,372 --> 00:52:20,570 ...much in their brains that would be of enormous interest to ours. 790 00:52:21,310 --> 00:52:22,800 And vice versa. 791 00:52:23,012 --> 00:52:24,912 I think extraterrestrial intelligence... 792 00:52:25,114 --> 00:52:27,912 ...even beings astonishingly more evolved than we... 793 00:52:28,117 --> 00:52:31,609 ...will be curious about us, about what we know, how we think... 794 00:52:31,821 --> 00:52:35,917 ...the course of our evolution, the prospects for our future. 795 00:52:36,992 --> 00:52:40,291 Within every human brain, patterns of electrochemical impulses... 796 00:52:40,496 --> 00:52:43,260 ...are continuously forming and dissipating. 797 00:52:43,466 --> 00:52:46,663 They reflect our emotions, ideas and memories. 798 00:52:46,869 --> 00:52:49,030 When recorded and amplified... 799 00:52:49,238 --> 00:52:52,002 ...these impulses sound like this. 800 00:52:54,944 --> 00:52:57,742 But would an extraterrestrial being, no matter how advanced... 801 00:52:57,947 --> 00:53:00,973 ...be able to read the mind that made these sounds? 802 00:53:01,183 --> 00:53:04,209 We ourselves are far from being able to do so. 803 00:53:04,954 --> 00:53:08,412 But in fact, we have sent the very impulses you are hearing... 804 00:53:08,624 --> 00:53:12,617 ...reflecting the emotions, ideas and memories of one human being... 805 00:53:12,828 --> 00:53:16,491 ...on a voyage to the stars. 806 00:53:23,772 --> 00:53:26,900 In August and September 1977... 807 00:53:27,109 --> 00:53:29,942 ...two Voyager spacecraft were launched... 808 00:53:30,145 --> 00:53:34,605 ...on an epic journey to the outer solar system and beyond. 809 00:53:35,150 --> 00:53:39,177 Their scientific mission was to explore the giant planets... 810 00:53:39,522 --> 00:53:41,353 ...first Jupiter and its satellites... 811 00:53:41,557 --> 00:53:44,651 ...and then Saturn and its system of moons. 812 00:53:52,701 --> 00:53:55,261 Close encounters with these great worlds... 813 00:53:55,471 --> 00:53:59,498 ...accelerate the Voyager spacecraft out of the solar system. 814 00:54:01,777 --> 00:54:04,541 As an incidental consequence of their trajectories... 815 00:54:04,747 --> 00:54:08,239 ...they will be carried inexorably into the realm of the stars... 816 00:54:08,450 --> 00:54:10,680 ...where they will wander forever. 817 00:54:12,588 --> 00:54:15,580 The ships will be slightly eroded within the solar system... 818 00:54:15,791 --> 00:54:18,624 ...by micrometeorites, planetary rings systems... 819 00:54:18,827 --> 00:54:20,886 ...and radiation belts. 820 00:54:24,833 --> 00:54:26,300 But once past the planets... 821 00:54:26,502 --> 00:54:29,130 ...they will endure for a billion years... 822 00:54:29,338 --> 00:54:32,739 ...in the cold vacuum of interstellar space. 823 00:54:33,776 --> 00:54:35,471 Perhaps in the distant future... 824 00:54:35,678 --> 00:54:39,307 ...beings of an alien civilization will intercept these ships. 825 00:54:39,515 --> 00:54:41,107 They'll examine our spacecraft... 826 00:54:41,317 --> 00:54:44,684 ...and understand much about our science and technology. 827 00:54:45,821 --> 00:54:49,848 But a machine alone can tell only so much about its makers. 828 00:54:50,059 --> 00:54:52,857 So each bears a golden phonograph record... 829 00:54:53,062 --> 00:54:55,997 ...with not only the brain waves of a woman from Earth... 830 00:54:56,198 --> 00:55:00,794 ...but also an anthology of music, pictures and sounds of our planet... 831 00:55:01,003 --> 00:55:04,200 ...including greetings in 60 human languages... 832 00:55:04,406 --> 00:55:07,671 ...and the salutations of the humpback whales. 833 00:55:07,876 --> 00:55:11,141 The record cover bears instructions on how to hear the sounds... 834 00:55:11,347 --> 00:55:13,542 ...and see the pictures encoded on the disk. 835 00:55:13,749 --> 00:55:17,685 Including some snapshots from the family album... 836 00:55:17,886 --> 00:55:19,979 ...of a distant world. 837 00:55:48,817 --> 00:55:51,650 The Voyager record is a message in a bottle... 838 00:55:51,854 --> 00:55:54,482 ...cast into the cosmic ocean. 839 00:55:54,690 --> 00:55:57,659 It contains some of our thoughts and our feelings... 840 00:55:57,860 --> 00:55:59,987 ...something of the information we store... 841 00:56:00,195 --> 00:56:03,631 ...in genes and brains and books. 842 00:56:05,067 --> 00:56:07,126 The recipients, if any... 843 00:56:07,336 --> 00:56:11,272 ...will understand the pictures and sounds incompletely at best. 844 00:56:11,473 --> 00:56:13,737 But one thing would be clear about us: 845 00:56:13,942 --> 00:56:16,740 No one sends such a message on such a journey... 846 00:56:16,945 --> 00:56:20,108 ...without a positive passion for the future. 847 00:56:20,315 --> 00:56:22,783 For all the possible vagaries of the message... 848 00:56:22,985 --> 00:56:26,148 ...they will be sure that we were a species endowed... 849 00:56:26,355 --> 00:56:30,724 ...with hope and perseverance, at least a little intelligence... 850 00:56:30,926 --> 00:56:35,192 ...and a longing to make contact with the cosmos.