1 00:00:05,805 --> 00:00:07,602 Freeman: What happens when we die? 2 00:00:09,843 --> 00:00:11,435 Do we simply cease to be? 3 00:00:14,047 --> 00:00:16,538 Or do we survive in some form? 4 00:00:18,818 --> 00:00:22,754 What is it that makes us unique, conscious beings? 5 00:00:22,822 --> 00:00:25,222 It's the greatest mystery of existence, 6 00:00:25,291 --> 00:00:29,660 a problem seemingly too big for science to solve. 7 00:00:29,729 --> 00:00:33,096 But today, a cluster of biologists, 8 00:00:33,166 --> 00:00:34,895 physicists, and philosophers 9 00:00:34,968 --> 00:00:38,836 are closing in on the answer to the ultimate question. 10 00:00:38,905 --> 00:00:42,363 Is there life after death? 11 00:00:47,914 --> 00:00:52,851 Space, time, life itself. 12 00:00:54,788 --> 00:00:59,555 The secrets of the cosmos lie Through the Wormhole. 13 00:01:09,469 --> 00:01:12,267 Is death the end? 14 00:01:12,338 --> 00:01:14,363 Eternal silence? 15 00:01:14,441 --> 00:01:16,170 Blackness? 16 00:01:16,242 --> 00:01:18,073 Nothingness? 17 00:01:18,144 --> 00:01:21,602 Or is there a spark inside of us 18 00:01:21,681 --> 00:01:25,515 that lives on beyond our physical selves? 19 00:01:25,585 --> 00:01:29,715 Philosophers and scientists have puzzled over that question 20 00:01:29,789 --> 00:01:32,257 for thousands of years. 21 00:01:32,325 --> 00:01:34,793 It's the great mystery - 22 00:01:34,861 --> 00:01:39,855 one that, sooner or later, we all have to face. 23 00:01:39,933 --> 00:01:43,664 One morning when I was 6 years old, 24 00:01:43,736 --> 00:01:47,502 my grandmother didn't wake up - 25 00:01:47,574 --> 00:01:50,668 then or ever again. 26 00:01:53,780 --> 00:01:56,180 It was my first experience with death. 27 00:01:56,249 --> 00:02:01,949 How could she be here yesterday but gone today? 28 00:02:02,021 --> 00:02:04,546 Was she gone forever? 29 00:02:04,624 --> 00:02:08,151 Or did some essential part of her live on? 30 00:02:12,298 --> 00:02:15,893 Christians and Muslims believe in a heaven for the just 31 00:02:15,969 --> 00:02:18,267 and a hell for sinners. 32 00:02:18,338 --> 00:02:20,772 Other religions see death as a transition 33 00:02:20,840 --> 00:02:22,967 to an existence on the higher plane 34 00:02:23,042 --> 00:02:26,205 or to another life here on Earth. 35 00:02:26,279 --> 00:02:29,407 All of these beliefs have one thing in common - 36 00:02:29,482 --> 00:02:32,974 the body is just a vessel for the soul, 37 00:02:33,052 --> 00:02:35,520 and the soul is eternal. 38 00:02:37,957 --> 00:02:40,892 This is something many believe in their hearts, 39 00:02:40,960 --> 00:02:47,331 but is there a way to prove it or disprove it scientifically? 40 00:02:47,400 --> 00:02:51,928 Eben Alexander taught and performed neurosurgery 41 00:02:52,005 --> 00:02:55,907 at the Harvard Medical School for 15 years. 42 00:02:55,975 --> 00:02:59,809 In 2008, his career took an unexpected turn - 43 00:02:59,879 --> 00:03:02,575 one that would give him profound insight 44 00:03:02,649 --> 00:03:06,176 into the possibility of life after death. 45 00:03:06,252 --> 00:03:10,689 He contracted an extremely rare form of bacterial meningitis 46 00:03:10,757 --> 00:03:13,726 and fell into a deep coma. 47 00:03:13,793 --> 00:03:16,193 I think if you were trying to come up 48 00:03:16,262 --> 00:03:18,059 with an experimental model 49 00:03:18,131 --> 00:03:21,692 that would best approach human death, 50 00:03:21,768 --> 00:03:24,635 meningitis is perfect because what it does 51 00:03:24,704 --> 00:03:28,140 is it attacks the entire outer surface of the brain. 52 00:03:28,208 --> 00:03:33,305 These are horizontal images taken through my skull, 53 00:03:33,379 --> 00:03:37,475 and you can see the entire outer surface of the brain 54 00:03:37,550 --> 00:03:39,313 was coated with pus. 55 00:03:39,385 --> 00:03:42,218 These bacteria had gotten rid of all the glucose, 56 00:03:42,288 --> 00:03:46,122 and now the only thing left to consumer were my brain cells, 57 00:03:46,192 --> 00:03:47,352 and so my entire neocortex - 58 00:03:47,427 --> 00:03:49,361 that part of the brain that makes us human - 59 00:03:49,429 --> 00:03:51,124 was completely shut down. 60 00:03:51,197 --> 00:03:54,530 Freeman: After seven days of virtual brain death, 61 00:03:54,601 --> 00:03:58,435 Alexander emerged from the coma. 62 00:03:58,504 --> 00:04:02,406 Miraculously, within a month, he was back to normal. 63 00:04:02,475 --> 00:04:05,740 But something happened to him while he was away. 64 00:04:05,812 --> 00:04:10,146 My first recollection from deep inside the coma 65 00:04:10,216 --> 00:04:12,684 was that I was - 66 00:04:12,752 --> 00:04:16,210 it's what I sometimes call the earthworm-eye view of the world. 67 00:04:16,289 --> 00:04:21,283 Everything was kind of murky, brown, red, dark. 68 00:04:21,361 --> 00:04:24,797 I literally remember roots over my head. 69 00:04:24,864 --> 00:04:28,766 And I seemed to be there for a very, very long time. 70 00:04:28,835 --> 00:04:31,736 I had no memory whatsoever of my life. 71 00:04:31,804 --> 00:04:34,136 No words - my language was gone. 72 00:04:34,207 --> 00:04:36,402 I was certainly not aware of anything going on around me 73 00:04:36,476 --> 00:04:37,909 in the ICU room. 74 00:04:37,977 --> 00:04:41,344 And then, in the midst of that, 75 00:04:41,414 --> 00:04:45,145 there was a little melody that was spinning in front of me. 76 00:04:45,218 --> 00:04:48,016 And it just started spinning and expanded, 77 00:04:48,087 --> 00:04:51,181 and it ended up clearing away 78 00:04:51,257 --> 00:04:55,990 all that ugly, foreboding, gross, muddy realm. 79 00:04:56,062 --> 00:04:57,552 And all of a sudden, 80 00:04:57,630 --> 00:05:02,829 I was coming up into this beautiful meadow. 81 00:05:02,902 --> 00:05:04,529 I had no body awareness. 82 00:05:04,604 --> 00:05:06,799 I had no arms, legs, or anything, 83 00:05:06,873 --> 00:05:10,400 but I was aware that I was a speck on a butterfly wing - 84 00:05:10,476 --> 00:05:13,707 absolutely beautiful butterfly. 85 00:05:13,780 --> 00:05:17,739 And there were millions of other colorful butterflies 86 00:05:17,817 --> 00:05:19,808 looping and swirling all around us, 87 00:05:19,886 --> 00:05:22,218 all in this beautiful formation of flying. 88 00:05:22,288 --> 00:05:26,452 And then we left this universe 89 00:05:26,526 --> 00:05:30,690 and went out into what I now call the core. 90 00:05:30,763 --> 00:05:35,291 At first, it seemed infinitely huge and dark, 91 00:05:35,368 --> 00:05:38,599 although I was there 92 00:05:38,671 --> 00:05:43,870 with that beautiful, warm awareness of the divine, 93 00:05:43,943 --> 00:05:47,276 which was clearly what we would call God 94 00:05:47,347 --> 00:05:50,043 in this place outside the universe. 95 00:05:50,116 --> 00:05:53,552 Basically, I recall the whole multiverse 96 00:05:53,619 --> 00:05:55,052 being out in front of me. 97 00:05:55,121 --> 00:05:58,648 It was very clear that love was a huge part 98 00:05:58,725 --> 00:06:01,057 of the constituent of that whole multiverse. 99 00:06:03,196 --> 00:06:05,630 Freeman: Alexander had faced something 100 00:06:05,698 --> 00:06:08,690 that tens of thousands of people have reported - 101 00:06:08,768 --> 00:06:10,736 a near-death experience. 102 00:06:10,803 --> 00:06:12,464 Nearly all claim something 103 00:06:12,538 --> 00:06:15,632 that science has so far been unable to prove - 104 00:06:15,708 --> 00:06:20,702 that there is another existence beyond the one we know. 105 00:06:20,780 --> 00:06:22,475 Dr. Alexander: This was something 106 00:06:22,548 --> 00:06:25,574 that was very difficult for me to explain 107 00:06:25,651 --> 00:06:27,881 from a neuroscientific standpoint, 108 00:06:27,954 --> 00:06:32,584 and the scientific side of me could not see how that could be, 109 00:06:32,658 --> 00:06:34,421 and yet it was a very, very powerful - 110 00:06:34,494 --> 00:06:36,485 very powerful memory. 111 00:06:36,562 --> 00:06:38,587 I came up with several models having to do 112 00:06:38,664 --> 00:06:41,189 with the neurophysiology and neuroanatomy. 113 00:06:41,267 --> 00:06:46,466 And the problem is none of those models sufficiently explain 114 00:06:46,539 --> 00:06:50,236 the very powerful memories that I brought back with me 115 00:06:50,309 --> 00:06:51,970 from this experience. 116 00:06:52,044 --> 00:06:57,846 And I ended up at a point where I do not believe 117 00:06:57,917 --> 00:07:02,718 that there is a good neurophysiologic explanation 118 00:07:02,789 --> 00:07:04,256 for what happened to me. 119 00:07:04,323 --> 00:07:06,257 Freeman: Eben Alexander's experience 120 00:07:06,325 --> 00:07:10,022 was profound and life-altering. 121 00:07:10,096 --> 00:07:13,088 But it is by no means unique. 122 00:07:16,536 --> 00:07:18,299 Bruce Greyson is a psychiatrist 123 00:07:18,371 --> 00:07:20,965 at the University of Virginia School of Medicine. 124 00:07:21,040 --> 00:07:23,907 He has investigated more than 1,000 cases 125 00:07:23,976 --> 00:07:25,910 of near-death experiences. 126 00:07:28,748 --> 00:07:31,410 The consistent features of a near-death experience 127 00:07:31,484 --> 00:07:35,716 are a sense of profound peace and well-being, 128 00:07:35,788 --> 00:07:38,120 a sense of leaving the physical body, 129 00:07:38,191 --> 00:07:40,557 a sense of brilliant light 130 00:07:40,626 --> 00:07:44,392 which seems to radiate warmth and unconditional love. 131 00:07:44,464 --> 00:07:47,456 Sometimes people report encountering other beings, 132 00:07:47,533 --> 00:07:49,125 including a deity of some kind. 133 00:07:49,202 --> 00:07:52,660 Sometimes they identify that deity as God or Christ, 134 00:07:52,738 --> 00:07:54,103 and sometimes they don't. 135 00:07:54,173 --> 00:07:55,435 They just say that there was 136 00:07:55,508 --> 00:07:57,373 this all-powerful being that they met. 137 00:07:57,443 --> 00:08:00,435 Freeman: Many scientists dismiss these experiences 138 00:08:00,513 --> 00:08:02,640 as nothing more than hallucinations 139 00:08:02,715 --> 00:08:05,843 triggered by a brain undergoing immense physical stress, 140 00:08:05,918 --> 00:08:11,754 mostly due to the nerve cells being deprived of oxygen. 141 00:08:11,824 --> 00:08:14,657 Back in the 1970s, 142 00:08:14,727 --> 00:08:16,752 experiments by the U.S. Air Force 143 00:08:16,829 --> 00:08:19,662 inadvertently tested this idea. 144 00:08:19,732 --> 00:08:22,724 Scientists spun pilots in a centrifuge, 145 00:08:22,802 --> 00:08:26,260 subjecting their bodies to massive G-forces. 146 00:08:26,339 --> 00:08:29,570 It caused blood to drain to their feet 147 00:08:29,642 --> 00:08:33,078 and left their brains starved for oxygen. 148 00:08:33,145 --> 00:08:35,272 They invariably blacked out. 149 00:08:35,348 --> 00:08:39,375 When they awoke, some pilots reported seeing a bright light. 150 00:08:39,452 --> 00:08:41,682 Others said they left their bodies 151 00:08:41,754 --> 00:08:44,416 and looked down at themselves from above - 152 00:08:44,490 --> 00:08:46,822 experiences similar to those of people 153 00:08:46,893 --> 00:08:49,088 who have been to the brink of death, 154 00:08:49,161 --> 00:08:52,255 but lacking one key feature. 155 00:08:52,331 --> 00:08:54,231 In the period when they were losing oxygen, 156 00:08:54,300 --> 00:08:55,699 as they were losing consciousness, 157 00:08:55,768 --> 00:08:57,133 they had some features 158 00:08:57,203 --> 00:08:59,831 which bear some similarities to near-death experiences. 159 00:08:59,906 --> 00:09:03,364 However, they certainly didn't ever meet deceased loved ones 160 00:09:03,442 --> 00:09:05,307 or other entities. 161 00:09:05,378 --> 00:09:10,372 The problem with all of these physiological explanations 162 00:09:10,449 --> 00:09:15,443 is that they don't account for the complex thinking, 163 00:09:15,521 --> 00:09:18,979 the memory formation, the perceptions that take place 164 00:09:19,058 --> 00:09:20,855 when we know the brain 165 00:09:20,927 --> 00:09:23,862 is not capable of doing complex thinking. 166 00:09:23,930 --> 00:09:26,490 Freeman: Are near-death experiences 167 00:09:26,566 --> 00:09:30,662 the final dream of a mind that's about to wink out of existence? 168 00:09:30,736 --> 00:09:36,038 Or are they a sign that there is something beyond death? 169 00:09:36,108 --> 00:09:39,373 Finding the truth requires nothing less 170 00:09:39,445 --> 00:09:43,506 than a scientific quest to discover the human soul. 171 00:09:43,583 --> 00:09:46,051 Is the soul a myth 172 00:09:46,118 --> 00:09:49,918 or one of the fundamental elements of the universe? 173 00:09:58,965 --> 00:10:01,593 For scientists, the question of life after death 174 00:10:01,667 --> 00:10:05,034 is inextricably linked with another question. 175 00:10:05,104 --> 00:10:07,265 What is consciousness? 176 00:10:07,340 --> 00:10:09,865 Where does consciousness come from? 177 00:10:09,942 --> 00:10:13,207 And where does it go when we die? 178 00:10:16,949 --> 00:10:18,780 Dr. Stuart Hameroff is the Director 179 00:10:18,851 --> 00:10:23,550 of Consciousness Studies at the University of Arizona, Tucson. 180 00:10:25,825 --> 00:10:28,692 He's also a practicing anesthesiologist. 181 00:10:40,740 --> 00:10:44,073 Under anesthesia, patients don't dream - 182 00:10:44,143 --> 00:10:45,701 even though I said, "pick out a nice dream." 183 00:10:45,778 --> 00:10:47,336 We always say that. But there's no awareness. 184 00:10:47,413 --> 00:10:49,847 There's no passage of time. Patients wake up. 185 00:10:49,915 --> 00:10:52,679 They don't know if they've been asleep five minutes or five hours. 186 00:10:52,752 --> 00:10:55,550 Anesthesia takes away consciousness. 187 00:10:55,621 --> 00:10:57,486 Brain under anesthesia is quite active. 188 00:10:57,556 --> 00:11:00,252 And the difference is still somewhat mysterious. 189 00:11:02,561 --> 00:11:04,620 Freeman: Years watching over patients in the operating room 190 00:11:04,697 --> 00:11:07,894 made Hameroff obsessed with understanding the link 191 00:11:07,967 --> 00:11:12,165 between brain activity and consciousness. 192 00:11:12,238 --> 00:11:14,502 Then, 15 years ago, 193 00:11:14,573 --> 00:11:18,737 he met the great British physicist, Sir Roger Penrose. 194 00:11:18,811 --> 00:11:21,780 Together, they developed a radical new theory 195 00:11:21,847 --> 00:11:23,405 for how the brain works - 196 00:11:23,482 --> 00:11:26,007 a theory that has grown into nothing less 197 00:11:26,085 --> 00:11:30,021 than a scientific argument for an eternal soul. 198 00:11:30,089 --> 00:11:34,185 At its root are tiny structures inside our brain cells 199 00:11:34,260 --> 00:11:36,751 called microtubules. 200 00:11:39,165 --> 00:11:40,757 Dr. Hameroff: If you look inside a cell, 201 00:11:40,833 --> 00:11:42,460 you find these structural components 202 00:11:42,535 --> 00:11:45,971 that are somewhat like the bones within our bodies. 203 00:11:46,038 --> 00:11:48,472 The microtubules develop literally a forest 204 00:11:48,541 --> 00:11:50,065 inside each cell, 205 00:11:50,142 --> 00:11:51,700 which determines the architecture 206 00:11:51,777 --> 00:11:53,074 and the structure of the cell. 207 00:11:53,145 --> 00:11:56,637 And we think microtubules are perfectly designed 208 00:11:56,716 --> 00:11:58,616 to be the cell's onboard computer 209 00:11:58,684 --> 00:12:01,346 and process information at the molecular level. 210 00:12:01,420 --> 00:12:04,548 Freeman: Hameroff and Penrose argue that microtubules 211 00:12:04,623 --> 00:12:07,353 allow neurons and the brain as a whole 212 00:12:07,426 --> 00:12:10,190 to function as a quantum computer, 213 00:12:10,262 --> 00:12:12,992 performing operations in a fundamentally different way 214 00:12:13,065 --> 00:12:16,466 from normal computers. 215 00:12:16,535 --> 00:12:19,026 Dr. Hameroff: So, here we have a brain with two hemispheres. 216 00:12:19,105 --> 00:12:20,470 Most views of the brain 217 00:12:20,539 --> 00:12:23,030 are of a collection of individual neurons. 218 00:12:23,109 --> 00:12:24,474 When one neuron fires, 219 00:12:24,543 --> 00:12:27,137 it sends a signal to the next neuron at a synapse. 220 00:12:27,213 --> 00:12:29,443 That, in turn, causes that neuron to fire, 221 00:12:29,515 --> 00:12:31,608 and that neuron causes another neuron to fire, 222 00:12:31,684 --> 00:12:33,083 much like dominoes. 223 00:12:33,152 --> 00:12:35,985 So, for example, if a neuron fires here, 224 00:12:36,055 --> 00:12:37,522 it's gonna trigger its neighbors to fire, 225 00:12:37,590 --> 00:12:40,821 sending signals through and around the brain. 226 00:12:40,893 --> 00:12:43,327 That's the classical view of how the brain works. 227 00:12:45,598 --> 00:12:48,328 Freeman: In a conventional computer, 228 00:12:48,400 --> 00:12:50,527 signals move around from place to place 229 00:12:50,603 --> 00:12:54,733 along traceable paths. 230 00:12:54,807 --> 00:12:57,401 But the microscopic components of a quantum computer 231 00:12:57,476 --> 00:13:03,415 are connected via a mysterious process called entanglement. 232 00:13:03,482 --> 00:13:06,645 Some of us think that quantum processes 233 00:13:06,719 --> 00:13:09,119 play an important role in consciousness in the brain. 234 00:13:09,188 --> 00:13:12,021 So, for example, if there's neuronal activity here, 235 00:13:12,091 --> 00:13:14,685 it may be coupled through quantum non-locality 236 00:13:14,760 --> 00:13:16,591 to processes over here. 237 00:13:16,662 --> 00:13:18,857 These neurons are connected 238 00:13:18,931 --> 00:13:20,330 even though they're spatially separated 239 00:13:20,399 --> 00:13:21,923 so that activity here 240 00:13:22,001 --> 00:13:25,129 instantaneously affects activity over here. 241 00:13:25,204 --> 00:13:28,731 Freeman: Hameroff and Penrose argue 242 00:13:28,808 --> 00:13:31,572 that a change in the microtubules in one brain cell 243 00:13:31,644 --> 00:13:34,044 can affect microtubules in another. 244 00:13:34,113 --> 00:13:36,445 But that's not all. 245 00:13:36,515 --> 00:13:40,076 Quantum theory claims that every single point in space, 246 00:13:40,152 --> 00:13:44,748 even empty space, can contain information. 247 00:13:44,824 --> 00:13:46,724 In the very fine structure of the universe, 248 00:13:46,792 --> 00:13:49,488 there is information, quantum information, 249 00:13:49,562 --> 00:13:51,325 not unlike these dominoes, 250 00:13:51,397 --> 00:13:55,197 so that we can have information up or down, here and here, 251 00:13:55,267 --> 00:13:56,632 but they're connected 252 00:13:56,702 --> 00:13:58,533 so that something that happens here 253 00:13:58,604 --> 00:13:59,935 influences something here. 254 00:14:00,005 --> 00:14:04,704 Freeman: This means the information in the microtubules 255 00:14:04,777 --> 00:14:06,836 can connect and become entangled 256 00:14:06,912 --> 00:14:09,904 with the universe outside the brain. 257 00:14:13,552 --> 00:14:16,612 Dr. Hameroff: So, just like these two neurons may be entangled, 258 00:14:16,689 --> 00:14:19,419 it's possible that the information of consciousness, 259 00:14:19,491 --> 00:14:21,322 of the whole brain, is entangled 260 00:14:21,393 --> 00:14:23,486 and can exist in the universe at large. 261 00:14:25,331 --> 00:14:27,094 Freeman: According to Hameroff, 262 00:14:27,166 --> 00:14:29,498 our souls are built from something 263 00:14:29,568 --> 00:14:32,469 much more fundamental than neurons. 264 00:14:32,538 --> 00:14:36,440 They are constructed from the very fabric of the universe. 265 00:14:38,644 --> 00:14:41,169 Dr. Hameroff: I think that consciousness or its immediate precursor - 266 00:14:41,247 --> 00:14:42,976 we'll call it proto-consciousness, 267 00:14:43,048 --> 00:14:44,777 has been in the universe all along, 268 00:14:44,850 --> 00:14:46,784 perhaps from the Big Bang. 269 00:14:52,291 --> 00:14:56,887 Freeman: All of this recalls the Buddhist and Hindu belief 270 00:14:56,962 --> 00:14:59,897 that consciousness is an integral part of the universe, 271 00:14:59,965 --> 00:15:04,664 and perhaps it is all there is in the universe. 272 00:15:06,839 --> 00:15:09,330 If consciousness is a quantum process, 273 00:15:09,408 --> 00:15:11,467 it may solve the mystery of what happens 274 00:15:11,543 --> 00:15:15,001 during near-death experiences. 275 00:15:15,080 --> 00:15:17,776 Dr. Hameroff: Let's say the heart stops beating, 276 00:15:17,850 --> 00:15:19,613 the blood stops flowing, 277 00:15:19,685 --> 00:15:22,210 the microtubules lose their quantum state. 278 00:15:22,288 --> 00:15:26,520 But the quantum information, which is in the microtubules, 279 00:15:26,592 --> 00:15:28,082 isn't destroyed. 280 00:15:28,160 --> 00:15:29,252 It can't be destroyed. 281 00:15:29,328 --> 00:15:31,091 It just distributes and dissipates 282 00:15:31,163 --> 00:15:32,460 to the universe at large. 283 00:15:32,531 --> 00:15:35,864 If the patient is resuscitated, revived, 284 00:15:35,935 --> 00:15:38,836 this quantum information can go back into the microtubules, 285 00:15:38,904 --> 00:15:41,634 and the patient says, "I had a near-death experience. 286 00:15:41,707 --> 00:15:43,868 I saw white light. I saw a tunnel. 287 00:15:43,943 --> 00:15:45,376 I saw my dead relatives. 288 00:15:45,444 --> 00:15:47,571 I maybe even floated out of my body." 289 00:15:47,646 --> 00:15:51,241 Now, if they're not revived and the patient dies, 290 00:15:51,317 --> 00:15:54,218 then it's possible that this quantum information 291 00:15:54,286 --> 00:15:57,881 can exist outside the body, perhaps indefinitely as a soul. 292 00:16:00,492 --> 00:16:02,722 Freeman: Many scientists find it difficult to believe 293 00:16:02,795 --> 00:16:05,320 that the soul is a quantum computer, 294 00:16:05,397 --> 00:16:07,194 hard-wired into the cosmos. 295 00:16:07,266 --> 00:16:11,760 But Hameroff feels that research is slowly validating his claims. 296 00:16:11,837 --> 00:16:14,897 Quantum effects have recently been shown 297 00:16:14,974 --> 00:16:18,068 to control several important biological processes, 298 00:16:18,143 --> 00:16:22,136 from bird navigation to photosynthesis 299 00:16:22,214 --> 00:16:25,149 to the human sense of smell. 300 00:16:25,217 --> 00:16:28,914 Dr. Hameroff: So far, nobody has landed a serious blow to the theory. 301 00:16:28,988 --> 00:16:32,617 We're still very viable, and evidence continues - 302 00:16:32,691 --> 00:16:35,660 new evidence continues to support the ideas 303 00:16:35,728 --> 00:16:37,491 that we put forth 15 years ago. 304 00:16:37,563 --> 00:16:39,895 Freeman: But the truth is 305 00:16:39,965 --> 00:16:42,832 we still don't know where consciousness comes from 306 00:16:42,901 --> 00:16:45,529 or where it goes when we die. 307 00:16:45,604 --> 00:16:49,233 If there was a way to measure consciousness, 308 00:16:49,308 --> 00:16:52,835 perhaps we could find the answers to these questions. 309 00:16:52,911 --> 00:16:55,402 That way may be coming soon, 310 00:16:55,481 --> 00:17:00,077 as one scientist explores the depths of our minds, 311 00:17:00,152 --> 00:17:03,417 hoping to discover the mysterious mental pattern 312 00:17:03,489 --> 00:17:06,253 that makes us who we are. 313 00:17:11,797 --> 00:17:14,197 The human brain isn't very big - 314 00:17:14,266 --> 00:17:16,962 3 pounds of soft tissue. 315 00:17:17,036 --> 00:17:21,973 But it can generate ideas that transform the world. 316 00:17:22,041 --> 00:17:25,067 It can hold personalities as diverse 317 00:17:25,144 --> 00:17:28,910 as Martin Luther King and Genghis Khan. 318 00:17:28,981 --> 00:17:31,381 It even knows what it is. 319 00:17:31,450 --> 00:17:34,351 It's self-aware. 320 00:17:34,420 --> 00:17:37,947 We think it has a soul. 321 00:17:38,023 --> 00:17:41,151 But where does that soul come from? 322 00:17:41,226 --> 00:17:44,753 Is consciousness a product of the brain? 323 00:17:44,830 --> 00:17:47,230 And can it outlive the brain? 324 00:17:47,299 --> 00:17:51,292 Studying what happens to the human brain when people die 325 00:17:51,370 --> 00:17:52,894 is not easy. 326 00:17:52,971 --> 00:17:55,439 Death rarely comes on cue. 327 00:17:55,507 --> 00:17:59,705 But one aspect of death comes to all of us every day. 328 00:17:59,778 --> 00:18:05,273 Each night when we fall asleep, our consciousness slips away. 329 00:18:07,953 --> 00:18:11,445 Professor Giulio Tononi of the University of Wisconsin 330 00:18:11,523 --> 00:18:14,185 is studying how our brains change 331 00:18:14,259 --> 00:18:16,124 when they lose consciousness, 332 00:18:16,195 --> 00:18:18,129 and in doing so, 333 00:18:18,197 --> 00:18:22,998 he's hoping to unravel the secret of what makes us us. 334 00:18:23,068 --> 00:18:24,865 The simplest definition of consciousness - 335 00:18:24,937 --> 00:18:28,100 that which goes away when you fall into dreamless sleep. 336 00:18:28,173 --> 00:18:29,663 But the fact of the matter is, 337 00:18:29,741 --> 00:18:31,572 the brain doesn't shut off at all. 338 00:18:31,643 --> 00:18:34,771 The neurons, the nerve cells, are actually just as active, 339 00:18:34,847 --> 00:18:37,680 in a sense, as they are when you are awake. 340 00:18:37,749 --> 00:18:40,775 So, it is an interesting scientific question. 341 00:18:40,853 --> 00:18:43,219 How would it be, then, that you disappear 342 00:18:43,288 --> 00:18:45,722 when your brain is still there and buzzing along? 343 00:18:45,791 --> 00:18:48,521 Freeman: Tononi believes our level of awareness 344 00:18:48,594 --> 00:18:50,619 is determined by how much information 345 00:18:50,696 --> 00:18:53,790 the different parts of our brain share with each other. 346 00:18:53,866 --> 00:18:56,300 An experience rich in detail 347 00:18:56,368 --> 00:18:59,462 will generate highly complex patterns in the brain, 348 00:18:59,538 --> 00:19:04,305 creating unique shapes that Tononi believes can be measured. 349 00:19:04,376 --> 00:19:07,937 Every experience is essentially like an extraordinary shape. 350 00:19:08,013 --> 00:19:12,313 Just like a fire with wonderful flames 351 00:19:12,384 --> 00:19:15,217 is an extraordinary shape that changes all the time. 352 00:19:15,287 --> 00:19:18,415 Now, it's a shape which is characterized 353 00:19:18,490 --> 00:19:21,254 by something I would call informational relationships. 354 00:19:21,326 --> 00:19:24,295 But it's a shape that shines of inner light. 355 00:19:24,363 --> 00:19:27,093 The fire of consciousness is a very special fire 356 00:19:27,166 --> 00:19:29,066 that's generated inside the brain, 357 00:19:29,134 --> 00:19:32,001 and it requires a very special set of ingredients 358 00:19:32,070 --> 00:19:34,231 in order to be able to burn and shine. 359 00:19:34,306 --> 00:19:37,605 Freeman: But understanding when that fire is lit 360 00:19:37,676 --> 00:19:39,906 and when it is extinguished 361 00:19:39,978 --> 00:19:44,142 is far more difficult than simply reading a brain scan. 362 00:19:44,216 --> 00:19:48,482 So Giulio Tononi built an entire lab 363 00:19:48,554 --> 00:19:52,991 dedicated to the unconscious netherworld of dreamless sleep. 364 00:19:53,058 --> 00:19:56,459 And he designed an experiment to detect how the brain changes 365 00:19:56,528 --> 00:19:58,291 when we lose consciousness. 366 00:19:58,363 --> 00:20:00,297 It's the neurological equivalent 367 00:20:00,365 --> 00:20:03,095 of knocking at the door of a darkened house 368 00:20:03,168 --> 00:20:05,659 to find out whether anyone is home. 369 00:20:05,737 --> 00:20:08,103 Tononi: We use something called 370 00:20:08,173 --> 00:20:10,004 transcranium magnetic stimulation, 371 00:20:10,075 --> 00:20:14,011 which is a way to inject a little current in the brain 372 00:20:14,079 --> 00:20:15,944 without having to open it up, 373 00:20:16,014 --> 00:20:18,312 so in a perfectly innocuous way, 374 00:20:18,383 --> 00:20:22,479 and then see how our cerebral cortex reacts to it. 375 00:20:22,554 --> 00:20:24,681 Freeman: First, the team runs the experiment 376 00:20:24,756 --> 00:20:26,883 on a volunteer who's awake. 377 00:20:26,959 --> 00:20:28,927 A mesh of electrodes will keep track 378 00:20:28,994 --> 00:20:30,985 of all activity in his brain. 379 00:20:31,063 --> 00:20:34,726 Now a small magnetic coil is placed on his head. 380 00:20:34,800 --> 00:20:38,167 At the flip of a switch, it delivers a pulse of magnetism 381 00:20:38,237 --> 00:20:42,469 lasting a tenth of a second to his cerebral cortex. 382 00:20:42,541 --> 00:20:45,977 The burst causes neurons in a small patch of the brain 383 00:20:46,044 --> 00:20:47,477 to fire, 384 00:20:47,546 --> 00:20:49,810 and they, in turn, send signals to other neurons, 385 00:20:49,881 --> 00:20:52,816 making them fire, as well. 386 00:20:52,884 --> 00:20:55,352 This complex pattern of neural activity 387 00:20:55,420 --> 00:20:58,821 spreads out to cover about a third of the cortex 388 00:20:58,890 --> 00:21:03,657 and lasts for almost 1/3 of a second. 389 00:21:03,729 --> 00:21:06,926 The conscious brain reverberates like a ringing bell. 390 00:21:06,999 --> 00:21:09,763 Someone is definitely home. 391 00:21:09,835 --> 00:21:13,362 But what happens when he's unconscious? 392 00:21:13,438 --> 00:21:15,463 Now that Brady is asleep, 393 00:21:15,540 --> 00:21:17,940 we are going to ring the bell again 394 00:21:18,010 --> 00:21:23,004 and see how his brain responds when - after falling asleep. 395 00:21:25,083 --> 00:21:27,881 Freeman: Once again, the brain lights up. 396 00:21:27,953 --> 00:21:32,083 But this time, there is no reverberation. 397 00:21:32,157 --> 00:21:33,647 The ring of the bell dies 398 00:21:33,725 --> 00:21:36,592 as quickly as the pulse of magnetism shuts off. 399 00:21:36,662 --> 00:21:39,256 The sleeping brain may be active, 400 00:21:39,331 --> 00:21:42,027 but it has lost the ability to share information 401 00:21:42,100 --> 00:21:45,399 between one part of the brain and another. 402 00:21:45,470 --> 00:21:48,928 Tononi believes this spreading of information 403 00:21:49,007 --> 00:21:52,636 is the key ingredient of consciousness. 404 00:21:52,711 --> 00:21:55,680 The waking brain keeps specialized areas 405 00:21:55,747 --> 00:21:57,510 in constant conversation, 406 00:21:57,582 --> 00:21:58,947 like a cabinet meeting 407 00:21:59,017 --> 00:22:01,986 with the secretary of state, treasury, and defense 408 00:22:02,054 --> 00:22:05,455 all deciding on a unified plan of action. 409 00:22:05,524 --> 00:22:08,789 When the brain is asleep, the meeting adjourns. 410 00:22:08,860 --> 00:22:12,796 The specialists leave, and nothing gets decided. 411 00:22:12,864 --> 00:22:14,126 Why do you lose consciousness 412 00:22:14,199 --> 00:22:16,326 when you are in deep sleep early in the night? 413 00:22:16,401 --> 00:22:18,961 The specialists that normally do talk to each other 414 00:22:19,037 --> 00:22:21,801 when you are awake - they stop doing so. 415 00:22:21,873 --> 00:22:24,933 There is some mechanism that comes into place when you sleep 416 00:22:25,010 --> 00:22:26,272 that makes the interaction 417 00:22:26,345 --> 00:22:27,937 between the specialists difficult. 418 00:22:28,013 --> 00:22:29,344 And, in the end, 419 00:22:29,414 --> 00:22:32,110 it looks like they can't talk to each other anymore, 420 00:22:32,184 --> 00:22:34,345 and not surprisingly, then, you lose consciousness. 421 00:22:34,419 --> 00:22:35,681 You're not there anymore. 422 00:22:35,754 --> 00:22:38,746 Freeman: Tononi's ability to tell the difference 423 00:22:38,824 --> 00:22:41,657 between a brain that's conscious and one that's not 424 00:22:41,727 --> 00:22:45,629 may soon find application in a medical setting, 425 00:22:45,697 --> 00:22:50,293 assessing the level of awareness of coma patients. 426 00:22:50,369 --> 00:22:52,803 Tononi: One of the first things you would want to know is, 427 00:22:52,871 --> 00:22:54,270 is anybody home? 428 00:22:54,339 --> 00:22:59,777 If that somebody is your wife or your son or your mother 429 00:22:59,845 --> 00:23:01,938 and you see the eyes are open 430 00:23:02,013 --> 00:23:04,379 and you don't know whether somebody's there, 431 00:23:04,449 --> 00:23:06,974 maybe even suffering, how do you go about that? 432 00:23:07,052 --> 00:23:09,919 Freeman: Giulio Tononi has found a way 433 00:23:09,988 --> 00:23:12,889 to see consciousness in the human brain, 434 00:23:12,958 --> 00:23:17,418 but exactly how it arises amid the complex web of neurons - 435 00:23:17,496 --> 00:23:21,762 that remains a mystery at which he can only begin to guess. 436 00:23:23,969 --> 00:23:26,164 Tononi: When one says that consciousness 437 00:23:26,238 --> 00:23:30,038 requires a complex system to support it, 438 00:23:30,108 --> 00:23:31,837 in some sense, that must be true. 439 00:23:31,910 --> 00:23:34,674 But the Internet is certainly very complex. 440 00:23:34,746 --> 00:23:36,976 Another example, you could also say 441 00:23:37,048 --> 00:23:40,575 that a chess-playing program is very complex. 442 00:23:40,652 --> 00:23:43,348 So there are many things that people intuitively call complex, 443 00:23:43,422 --> 00:23:44,821 but only a few of them 444 00:23:44,890 --> 00:23:46,915 seem to be able to give rise to consciousness. 445 00:23:46,992 --> 00:23:50,393 So what you need is the right kind of complexity, 446 00:23:50,462 --> 00:23:53,863 and only a few structures - as far as I can tell - 447 00:23:53,932 --> 00:23:56,833 can do that, can pull out that extraordinary feat. 448 00:23:56,902 --> 00:23:58,995 Our cortex, the cerebral cortex, 449 00:23:59,070 --> 00:24:01,868 seems to be wired up almost ideally 450 00:24:01,940 --> 00:24:03,703 to achieve exactly that. 451 00:24:08,346 --> 00:24:11,838 Freeman: But is there a way to discover the root of consciousness? 452 00:24:11,917 --> 00:24:14,408 And is this sense of self-awareness 453 00:24:14,486 --> 00:24:16,420 the same as the soul? 454 00:24:16,488 --> 00:24:20,151 This man thinks he's found the human soul 455 00:24:20,225 --> 00:24:23,626 and knows what happens to it when we die. 456 00:24:30,869 --> 00:24:33,337 What is the soul? 457 00:24:33,405 --> 00:24:36,101 Is it a field of energy? 458 00:24:36,174 --> 00:24:38,472 Is it something tangible? 459 00:24:38,543 --> 00:24:41,910 Does it have weight? 460 00:24:41,980 --> 00:24:45,541 In 1907, Dr. Duncan MacDougall determined 461 00:24:45,617 --> 00:24:50,418 that the soul weighs about 3/4 of an ounce, 462 00:24:50,489 --> 00:24:52,514 or 21 grams. 463 00:24:52,591 --> 00:24:57,688 He determined this by weighing the bodies of dying TB patients. 464 00:24:57,762 --> 00:25:00,128 But in the 100 years since then, 465 00:25:00,198 --> 00:25:03,827 no one has been able to replicate his findings 466 00:25:03,902 --> 00:25:10,102 because there doesn't seem to be anything to weigh. 467 00:25:12,277 --> 00:25:18,409 Could there be some elusive substance that makes you you? 468 00:25:18,483 --> 00:25:21,384 At the smallest levels of existence, 469 00:25:21,453 --> 00:25:23,717 all matter is made of atoms. 470 00:25:23,788 --> 00:25:27,349 Earth has been recycling atoms for billions of years. 471 00:25:27,425 --> 00:25:30,792 Carbon moves from trees to oceans 472 00:25:30,862 --> 00:25:32,523 to the cells in our bodies. 473 00:25:32,597 --> 00:25:37,830 Even the atoms of dead people get reused. 474 00:25:37,903 --> 00:25:40,997 This means that an atom in your thigh bone 475 00:25:41,072 --> 00:25:44,371 might have been part of Cleopatra's lower lip. 476 00:25:44,442 --> 00:25:49,778 And this recycling doesn't just happen at the atomic level. 477 00:25:49,848 --> 00:25:55,218 You are constantly rebuilding yourself at the cellular level. 478 00:25:55,287 --> 00:25:59,951 Your body produces 1 billion new cells every hour. 479 00:26:00,025 --> 00:26:01,652 No matter how old you are, 480 00:26:01,726 --> 00:26:06,322 most of you is no more than 10 years old. 481 00:26:06,398 --> 00:26:10,391 Christof Koch is a Professor of Biology and Engineering 482 00:26:10,468 --> 00:26:12,197 at CalTech. 483 00:26:12,270 --> 00:26:14,795 He believes that what makes you you 484 00:26:14,873 --> 00:26:18,536 has nothing to do with individual atoms or cells. 485 00:26:18,610 --> 00:26:22,011 He believes that "you" emerges from the unique way 486 00:26:22,080 --> 00:26:25,481 the cells in your brain are organized. 487 00:26:25,550 --> 00:26:28,212 The brain is the most complex piece of matter 488 00:26:28,286 --> 00:26:29,753 we know in the universe. 489 00:26:29,821 --> 00:26:31,755 The human brain typically is on the order 490 00:26:31,823 --> 00:26:34,155 of 100 billion nerve cells. 491 00:26:34,225 --> 00:26:37,661 Each of those is a very complicated entity by itself. 492 00:26:37,729 --> 00:26:39,754 It's more like a little computer, 493 00:26:39,831 --> 00:26:43,665 interconnected to 10,000 to 100,000 other nerve cells. 494 00:26:43,735 --> 00:26:47,762 Freeman: Separately, these neurons aren't conscious. 495 00:26:47,839 --> 00:26:50,967 But when they interact with each other on a massive scale, 496 00:26:51,042 --> 00:26:54,569 the result is a self-aware network. 497 00:26:54,646 --> 00:26:57,080 We believe that consciousness emerges 498 00:26:57,148 --> 00:27:00,948 out of the firing of millions or possibly billions of neurons. 499 00:27:01,019 --> 00:27:02,680 So that's what my soul is. 500 00:27:02,754 --> 00:27:05,086 That's what my feelings, my subjective feelings 501 00:27:05,156 --> 00:27:07,215 of pain and pleasure and of yearning are. 502 00:27:07,292 --> 00:27:09,658 Freeman: But if, as Koch believes, 503 00:27:09,728 --> 00:27:12,754 who we are stems exclusively from this fragile 504 00:27:12,831 --> 00:27:15,163 and ever-changing network of brain cells, 505 00:27:15,233 --> 00:27:17,827 then there can be no eternal you. 506 00:27:17,902 --> 00:27:19,233 Koch: We constantly change. 507 00:27:19,304 --> 00:27:21,329 With each experience, we change a little bit. 508 00:27:21,406 --> 00:27:23,203 With some experiences, we change more, 509 00:27:23,274 --> 00:27:25,367 and with other experiences, we change less. 510 00:27:25,443 --> 00:27:27,673 So, that sense, there's no constant. 511 00:27:27,746 --> 00:27:30,772 And as we age, again, my mind - my body, 512 00:27:30,849 --> 00:27:33,340 but also my personality and my mind changes. 513 00:27:33,418 --> 00:27:36,910 So, that sense, there's no constant personality. 514 00:27:36,988 --> 00:27:40,856 It's a changing construct of the brain and by the brain. 515 00:27:40,925 --> 00:27:45,385 Freeman: This view of the brain is called materialism, 516 00:27:45,463 --> 00:27:47,658 and Koch is its champion. 517 00:27:47,732 --> 00:27:49,097 For materialists, 518 00:27:49,167 --> 00:27:51,897 the soul is nothing more than a fleeting illusion, 519 00:27:51,970 --> 00:27:54,598 an illusion that cannot outlive 520 00:27:54,673 --> 00:27:57,073 the physical network from which it arises. 521 00:28:00,145 --> 00:28:02,875 Once that electrical traffic ceases 522 00:28:02,947 --> 00:28:04,915 because the brain itself doesn't work anymore 523 00:28:04,983 --> 00:28:06,951 and the neurons stop firing, 524 00:28:07,018 --> 00:28:11,045 then, also, the soul will cease to exist. 525 00:28:13,258 --> 00:28:16,750 Freeman: But renowned cognitive scientist Douglas Hofstadter 526 00:28:16,828 --> 00:28:20,355 is not so quick to dismiss the possibility of life after death. 527 00:28:20,432 --> 00:28:23,993 He believes the soul does not disappear the moment we die. 528 00:28:24,069 --> 00:28:26,537 Hofstadter: When I was a graduate student in physics, 529 00:28:26,604 --> 00:28:30,267 I had a professor who I was very fond of 530 00:28:30,341 --> 00:28:35,278 who was a religious person. 531 00:28:35,346 --> 00:28:41,216 And he believed, to my shock and surprise and confusion, 532 00:28:41,286 --> 00:28:43,720 that inside the brain, 533 00:28:43,788 --> 00:28:46,279 there were certain kinds of particles 534 00:28:46,357 --> 00:28:48,757 that we hadn't yet discovered 535 00:28:48,827 --> 00:28:52,160 that gave rise to soul and consciousness. 536 00:28:52,230 --> 00:28:54,460 Freeman: Hofstadter took a more scientific approach 537 00:28:54,532 --> 00:28:55,863 to the brain. 538 00:28:55,934 --> 00:28:59,563 He became a pioneer in modeling complex mental processes. 539 00:28:59,637 --> 00:29:02,572 He thinks about how people think. 540 00:29:02,640 --> 00:29:05,768 And what humans do best, in his opinion, 541 00:29:05,844 --> 00:29:09,302 is make mental maps of the world around them. 542 00:29:09,380 --> 00:29:12,440 The process of perceiving a world 543 00:29:12,517 --> 00:29:16,419 gives rise to internal representations of everything. 544 00:29:16,488 --> 00:29:18,956 You know, if I look at this pepper shaker, 545 00:29:19,023 --> 00:29:22,117 I have an internal model of it. 546 00:29:22,193 --> 00:29:23,785 And I don't need to look at it 547 00:29:23,862 --> 00:29:25,853 because I've seen it so many times, 548 00:29:25,930 --> 00:29:28,490 I have an internal model of it that is stable. 549 00:29:28,566 --> 00:29:32,161 Freeman: All animals make mental maps. 550 00:29:32,237 --> 00:29:35,934 The bigger the animal, the more complex the map. 551 00:29:36,007 --> 00:29:39,738 A bee knows the position of the sun and its hive. 552 00:29:39,811 --> 00:29:41,676 A manta ray learns to navigate 553 00:29:41,746 --> 00:29:46,183 the convoluted web of ocean currents. 554 00:29:46,251 --> 00:29:47,741 A baboon must keep track 555 00:29:47,819 --> 00:29:51,448 of the troop's social pecking order. 556 00:29:51,523 --> 00:29:52,888 Our maps are built 557 00:29:52,957 --> 00:29:55,949 from a lifetime of objects and people we've encountered... 558 00:29:56,027 --> 00:29:58,723 And one other crucial element. 559 00:29:58,797 --> 00:30:03,359 Hofstadter: We incorporate not only the rest of the world, 560 00:30:03,434 --> 00:30:05,800 but we incorporate our own understanding 561 00:30:05,870 --> 00:30:08,134 of who we are and what we are, 562 00:30:08,206 --> 00:30:12,336 which includes superficial, physical things 563 00:30:12,410 --> 00:30:14,241 like the fact that we have two hands 564 00:30:14,312 --> 00:30:16,542 and five fingers on each hand, 565 00:30:16,614 --> 00:30:19,208 what kind of sense of humor we have, 566 00:30:19,284 --> 00:30:22,412 whether we're good at throwing free-throws in basketball 567 00:30:22,487 --> 00:30:24,011 or hook shots. 568 00:30:24,088 --> 00:30:30,152 And we create a concept that reflects who we are. 569 00:30:30,228 --> 00:30:33,823 Freeman: Hofstadter regards this map of the world 570 00:30:33,898 --> 00:30:36,492 that also includes a map of the map-maker 571 00:30:36,568 --> 00:30:38,729 as a mental feedback loop. 572 00:30:40,672 --> 00:30:43,607 If you point a television camera at a television screen 573 00:30:43,675 --> 00:30:46,439 and then the screen gets put onto itself, 574 00:30:46,511 --> 00:30:47,944 et cetera, et cetera, 575 00:30:48,012 --> 00:30:50,776 and you get a very complex visual pattern - 576 00:30:50,849 --> 00:30:53,750 the system itself is perceiving itself. 577 00:30:53,818 --> 00:30:57,015 To me, the soul is an emergent process, 578 00:30:57,088 --> 00:30:59,420 an emergent entity that comes out of decades 579 00:30:59,490 --> 00:31:03,984 of perception and feedback. 580 00:31:04,062 --> 00:31:06,792 Freeman: But this view of consciousness 581 00:31:06,865 --> 00:31:08,765 has a shocking implication. 582 00:31:08,833 --> 00:31:12,496 If the soul is just a strange mental feedback loop, 583 00:31:12,570 --> 00:31:15,471 then it should not be unique to humans. 584 00:31:15,540 --> 00:31:20,136 Any sufficiently smart network should be able to experience it, 585 00:31:20,211 --> 00:31:22,270 whatever it is made of. 586 00:31:22,347 --> 00:31:24,747 Which is why this latter-day Frankenstein 587 00:31:24,816 --> 00:31:27,444 is planning to build a soul. 588 00:31:27,518 --> 00:31:31,249 What he learns could point the way to a life beyond death. 589 00:31:33,591 --> 00:31:39,029 Religion tells us that our souls transcend the body. 590 00:31:39,097 --> 00:31:45,002 These are just shells that we walk around in for a while. 591 00:31:45,069 --> 00:31:48,095 Most scientists don't believe that. 592 00:31:48,172 --> 00:31:50,800 They say that what we call the soul 593 00:31:50,875 --> 00:31:53,605 is a self-aware network of brain connections 594 00:31:53,678 --> 00:31:56,875 that evolved over millions of years. 595 00:31:56,948 --> 00:31:59,508 If that's true, 596 00:31:59,584 --> 00:32:05,113 then what would happen if we built a copy of the human brain? 597 00:32:05,189 --> 00:32:07,350 Would it have a soul? 598 00:32:07,425 --> 00:32:10,292 We're on the verge of finding out. 599 00:32:10,361 --> 00:32:12,192 And if the mystery of the mind 600 00:32:12,263 --> 00:32:14,959 is something we can crack computationally, 601 00:32:15,033 --> 00:32:20,528 it would even give us an escape route from death. 602 00:32:24,242 --> 00:32:27,143 Around the world, teams of researchers 603 00:32:27,211 --> 00:32:31,739 are attempting to reverse-engineer a human brain. 604 00:32:31,816 --> 00:32:35,445 It's a tough job, because for all our research, 605 00:32:35,520 --> 00:32:38,318 the brain is still the most complicated instrument 606 00:32:38,389 --> 00:32:41,017 in the known universe. 607 00:32:41,092 --> 00:32:44,220 But mapping the brain could take decades to complete, 608 00:32:44,295 --> 00:32:46,092 which is why some rebel scientists 609 00:32:46,164 --> 00:32:47,995 have decided to harness the firepower 610 00:32:48,066 --> 00:32:51,695 inside living brain cells. 611 00:32:51,769 --> 00:32:53,964 They're trying to crack the secrets of the soul 612 00:32:54,038 --> 00:32:58,134 by fusing biology and technology, 613 00:32:58,209 --> 00:33:02,942 taking bits of brain and mating them to bits of hardware. 614 00:33:03,014 --> 00:33:05,278 Most computer simulations 615 00:33:05,350 --> 00:33:09,650 are limited to very simplistic neurons. 616 00:33:09,721 --> 00:33:12,053 What we have here in our culture dishes 617 00:33:12,123 --> 00:33:15,149 with real, live, wet, squishy neurons 618 00:33:15,226 --> 00:33:16,716 with all their complexity, 619 00:33:16,794 --> 00:33:19,194 is immensely much more complicated 620 00:33:19,263 --> 00:33:21,458 than anything we can simulate on today's computers. 621 00:33:21,532 --> 00:33:24,399 Freeman: Professor Steve Potter 622 00:33:24,469 --> 00:33:26,835 of the Georgia Institute of Technology 623 00:33:26,904 --> 00:33:29,304 designs and builds brains - 624 00:33:29,374 --> 00:33:32,502 brains that are half-living, half-machine. 625 00:33:32,577 --> 00:33:37,344 Potter's team takes neurons cultured from rat embryos 626 00:33:37,415 --> 00:33:40,714 then grows them on miniature plates of electrodes. 627 00:33:40,785 --> 00:33:43,652 Potter: Here is a multi-electrode array culture dish. 628 00:33:43,721 --> 00:33:47,350 You can see some fluorescently labeled neurons growing on it. 629 00:33:47,425 --> 00:33:49,256 These are the electrodes 630 00:33:49,327 --> 00:33:52,524 with leads heading off to the electronics 631 00:33:52,597 --> 00:33:56,294 that we use to record from and stimulate the cells. 632 00:33:56,367 --> 00:33:58,665 These are all the axons and dendrites 633 00:33:58,736 --> 00:34:01,671 that represent the connections between the cells. 634 00:34:01,739 --> 00:34:04,674 Those connections form 635 00:34:04,742 --> 00:34:07,336 over the course of the first four hours in culture. 636 00:34:07,412 --> 00:34:09,846 You can see on this time lapse here 637 00:34:09,914 --> 00:34:11,711 connections forming. 638 00:34:11,783 --> 00:34:14,217 So, those are the synaptic connections 639 00:34:14,285 --> 00:34:16,344 by which the neurons talk to each other, 640 00:34:16,421 --> 00:34:19,857 and we can film that conversation in progress 641 00:34:19,924 --> 00:34:22,552 using a calcium-sensitive dye here. 642 00:34:22,627 --> 00:34:24,925 So, here you can see the cells flashing. 643 00:34:24,996 --> 00:34:27,123 Every time the cell sends a signal to another cell, 644 00:34:27,198 --> 00:34:28,688 it has a little burst of calcium. 645 00:34:28,766 --> 00:34:31,735 Freeman: When the brain has grown, 646 00:34:31,803 --> 00:34:35,432 potter send information to it through the electrodes, 647 00:34:35,506 --> 00:34:38,270 and the brain responds. 648 00:34:38,342 --> 00:34:40,867 Those electrodes are connected to a computer 649 00:34:40,945 --> 00:34:44,711 that's wired up to a robot body, 650 00:34:44,782 --> 00:34:47,615 resulting in a new form of life. 651 00:34:47,685 --> 00:34:50,245 This is hybrot - 652 00:34:50,321 --> 00:34:53,950 a robot controlled by living brain tissue. 653 00:34:54,025 --> 00:34:55,754 Its brains are in a refrigerator, 654 00:34:55,827 --> 00:34:59,729 but you can see its neurons react on the computer screen 655 00:34:59,797 --> 00:35:03,494 as its body finds its way around the lab bench. 656 00:35:03,568 --> 00:35:05,468 Like any animal, 657 00:35:05,536 --> 00:35:08,130 the hybrot has experiences and learns from them. 658 00:35:08,206 --> 00:35:11,937 In this case, how to navigate its environment. 659 00:35:12,009 --> 00:35:17,379 So, the question is, could a hybrot ever become conscious? 660 00:35:19,750 --> 00:35:24,244 Whether or not we could ever get to conscious cultured networks 661 00:35:24,322 --> 00:35:27,951 is a question which I would say we've already answered "yes." 662 00:35:28,025 --> 00:35:29,492 We have culture dishes 663 00:35:29,560 --> 00:35:31,494 that are receiving inputs from the environment. 664 00:35:31,562 --> 00:35:33,496 They're responding to them in complicated ways. 665 00:35:33,564 --> 00:35:36,294 So they're conscious of their environment 666 00:35:36,367 --> 00:35:37,959 in some very rudimentary fashion. 667 00:35:38,035 --> 00:35:40,162 Perhaps with more complicated interactions 668 00:35:40,238 --> 00:35:41,705 between different brain tissues 669 00:35:41,772 --> 00:35:43,706 and between the computer and the brain tissues, 670 00:35:43,774 --> 00:35:46,106 we could get to something that people would say 671 00:35:46,177 --> 00:35:49,943 is a high-level cognition, more like human consciousness. 672 00:35:50,014 --> 00:35:54,144 Freeman: But if one day a hybrot or a computer wakes up 673 00:35:54,218 --> 00:35:57,051 and realizes what and who it is, 674 00:35:57,121 --> 00:35:59,919 if a soul emerges from those wires, 675 00:35:59,991 --> 00:36:02,653 how would we know? 676 00:36:02,727 --> 00:36:06,128 We'll have to rely on conversation. 677 00:36:06,197 --> 00:36:09,132 If we asked the artificial brain, "Are you conscious?" 678 00:36:09,200 --> 00:36:11,225 And it persuades us that it is, 679 00:36:11,302 --> 00:36:13,361 we'll just have to take its word. 680 00:36:13,437 --> 00:36:16,201 But the same thing applies when we talk to other humans. 681 00:36:16,274 --> 00:36:19,402 We don't actually know that other people are conscious. 682 00:36:19,477 --> 00:36:23,140 They might just be zombies who are saying the right thing 683 00:36:23,214 --> 00:36:26,081 but having no private, subjective experience. 684 00:36:28,286 --> 00:36:32,017 I can put some sort of an artificial intelligence 685 00:36:32,089 --> 00:36:33,420 into a computer right now 686 00:36:33,491 --> 00:36:35,721 that represents the kind of decisions I might make 687 00:36:35,793 --> 00:36:39,422 and has, in some sense, some of my consciousness in it. 688 00:36:39,497 --> 00:36:41,226 So that's not hard to do. 689 00:36:41,299 --> 00:36:42,891 But to get something that we would say 690 00:36:42,967 --> 00:36:44,662 is a good enough copy of my consciousness 691 00:36:44,735 --> 00:36:47,397 that if it were put back in somebody else's body, 692 00:36:47,471 --> 00:36:50,065 people would be fooled into thinking it was me - 693 00:36:50,141 --> 00:36:52,769 this is something we haven't even the first clue 694 00:36:52,843 --> 00:36:55,403 of how to do it in any kind of a detailed way. 695 00:36:55,479 --> 00:36:59,575 Freeman: Building artificial homes for our souls 696 00:36:59,650 --> 00:37:02,141 may be a long time coming, 697 00:37:02,220 --> 00:37:04,984 so what do we do in the meantime? 698 00:37:05,056 --> 00:37:06,956 Turns out the ideal vessels 699 00:37:07,024 --> 00:37:10,084 to carry souls after the death of the body 700 00:37:10,161 --> 00:37:12,652 may already exist. 701 00:37:12,730 --> 00:37:16,325 One could be sitting right next to you. 702 00:37:19,537 --> 00:37:22,768 Despite our advanced technology, 703 00:37:22,840 --> 00:37:27,743 the riddle of life still seems a long way from being solved - 704 00:37:27,812 --> 00:37:31,646 Or... is it? 705 00:37:31,716 --> 00:37:34,184 In Bloomington, Indiana, 706 00:37:34,252 --> 00:37:39,246 Douglas Hofstadter says it's all a matter of perspective. 707 00:37:39,323 --> 00:37:42,690 He believes consciousness is the inevitable result 708 00:37:42,760 --> 00:37:44,591 of the strange and wonderful way 709 00:37:44,662 --> 00:37:46,892 the brain joins information together 710 00:37:46,964 --> 00:37:49,296 into patterns of thought. 711 00:37:49,367 --> 00:37:52,302 And the patterns of thought that form us 712 00:37:52,370 --> 00:37:55,237 are not unique to us. 713 00:37:55,306 --> 00:37:58,139 We are all curious collages 714 00:37:58,209 --> 00:38:01,269 of everyone we've ever been influenced by, 715 00:38:01,345 --> 00:38:03,813 living or dead. 716 00:38:03,881 --> 00:38:05,405 The pattern of your soul 717 00:38:05,483 --> 00:38:08,646 is the strongest and most complex in your own brain, 718 00:38:08,719 --> 00:38:11,711 but it can be passed on to other brains. 719 00:38:15,126 --> 00:38:17,356 Hofstadter: This is a book of Chopin études. 720 00:38:17,428 --> 00:38:21,865 These black splotches on white paper 721 00:38:21,932 --> 00:38:25,891 capture some very, very central pieces 722 00:38:25,970 --> 00:38:27,631 of Chopin's emotionality - 723 00:38:27,705 --> 00:38:32,199 his highs, his lows, 724 00:38:32,276 --> 00:38:33,709 his sense of triumph, 725 00:38:33,778 --> 00:38:37,407 his sense of resignation or anguish. 726 00:38:37,481 --> 00:38:41,110 Anything that was part of his emotional makeup comes through, 727 00:38:41,185 --> 00:38:44,018 and one gets a very deep glimpse of another human being. 728 00:38:44,088 --> 00:38:47,114 Perhaps 150, 160 years after that person 729 00:38:47,191 --> 00:38:51,127 has officially vanished from the surface of the Earth, 730 00:38:51,195 --> 00:38:53,220 something of their soul persists 731 00:38:53,297 --> 00:38:58,064 and invades the minds and brains of millions of other people. 732 00:38:58,135 --> 00:39:01,901 Freeman: This is a form of life after death 733 00:39:01,972 --> 00:39:03,872 that we all experience, 734 00:39:03,941 --> 00:39:06,876 though we may not recognize it for what it is. 735 00:39:09,013 --> 00:39:12,608 Freeman: It took a great personal tragedy for Hofstadter to see this - 736 00:39:12,683 --> 00:39:15,345 the death of his wife, Carol. 737 00:39:17,855 --> 00:39:19,322 We were in Italy, 738 00:39:19,390 --> 00:39:23,588 and it was a very sudden discovery of a brain tumor. 739 00:39:23,661 --> 00:39:26,892 And we found out that she had a brain tumor 740 00:39:26,964 --> 00:39:29,660 on the 11th of December, 741 00:39:29,734 --> 00:39:31,497 and on the 12th of December, in the evening, 742 00:39:31,569 --> 00:39:33,867 she fell into a coma. 743 00:39:33,938 --> 00:39:39,205 So it was very, very, very fast. 744 00:39:39,276 --> 00:39:41,744 When somebody that I have been entangled with 745 00:39:41,812 --> 00:39:43,643 for so long and so deeply 746 00:39:43,714 --> 00:39:46,114 is suddenly poofed out of existence, 747 00:39:46,183 --> 00:39:50,142 I then had to, you know, confront the question 748 00:39:50,221 --> 00:39:53,554 of what, if anything, survived 749 00:39:53,624 --> 00:39:55,489 and where, if at all, 750 00:39:55,559 --> 00:39:59,928 can a human soul be transplanted, 751 00:39:59,997 --> 00:40:02,898 uprooted from one brain to another brain? 752 00:40:02,967 --> 00:40:07,870 And my answer would have to be, 753 00:40:07,938 --> 00:40:11,465 in a very limited sense, yes. 754 00:40:11,542 --> 00:40:15,308 The degree to which Carol exists inside me - 755 00:40:15,379 --> 00:40:19,645 it's a much stripped-down version of her. 756 00:40:19,717 --> 00:40:23,312 It's a crude version. It's coarse-grained. 757 00:40:23,387 --> 00:40:25,855 It's as if one had a mosaic done 758 00:40:25,923 --> 00:40:30,451 in very, very small, fine stones - 759 00:40:30,528 --> 00:40:31,961 a million of them. 760 00:40:32,029 --> 00:40:34,190 And then it was a destroyed, 761 00:40:34,265 --> 00:40:36,199 but somebody, before it was destroyed, 762 00:40:36,267 --> 00:40:40,067 had made a copy of it but only using 1,000 stones. 763 00:40:40,137 --> 00:40:42,332 And so the 1,000 stones 764 00:40:42,406 --> 00:40:44,966 still have the same colors and the same kind of arrangement, 765 00:40:45,042 --> 00:40:47,943 but much more coarse-grained, in a different medium, 766 00:40:48,012 --> 00:40:49,604 in different stones. 767 00:40:49,680 --> 00:40:51,341 The original has been destroyed, 768 00:40:51,415 --> 00:40:56,648 but the copy exists in a coarse-grained version. 769 00:40:56,720 --> 00:40:59,746 Freeman: And so, we live on. 770 00:40:59,824 --> 00:41:02,224 A piece of our soul survives 771 00:41:02,293 --> 00:41:04,784 in everyone we have ever encountered. 772 00:41:04,862 --> 00:41:06,386 That soul fragment 773 00:41:06,464 --> 00:41:09,865 is the strongest, most recognizable 774 00:41:09,934 --> 00:41:11,799 in the people who loved us. 775 00:41:11,869 --> 00:41:15,828 This form of life after death is one we can all relate to, 776 00:41:15,906 --> 00:41:17,806 whatever our religion. 777 00:41:17,875 --> 00:41:21,777 But is there some other resting place for the soul? 778 00:41:21,846 --> 00:41:24,679 Does our consciousness just shimmer out of existence 779 00:41:24,748 --> 00:41:27,114 in our last moments on Earth? 780 00:41:27,184 --> 00:41:30,642 Is the soul nothing more than a network of neural processes, 781 00:41:30,721 --> 00:41:33,952 something that one day can be recreated in a machine? 782 00:41:34,024 --> 00:41:36,652 Or does the quantum state of our brain 783 00:41:36,727 --> 00:41:40,288 get reabsorbed into the universe at large? 784 00:41:40,364 --> 00:41:43,492 Scientists believe they are finally getting close 785 00:41:43,567 --> 00:41:45,558 to solving this puzzle, 786 00:41:45,636 --> 00:41:49,128 even though they passionately disagree about the answer. 787 00:41:49,206 --> 00:41:51,174 When you lose consciousness, you lose your soul. 788 00:41:51,242 --> 00:41:52,504 You lose everything. 789 00:41:52,576 --> 00:41:54,567 The world does not exist anymore for you. 790 00:41:54,645 --> 00:41:56,840 Your friends don't exist anymore. 791 00:41:56,914 --> 00:41:59,178 You don't exist. Everything is lost. 792 00:41:59,250 --> 00:42:02,310 If you take these near-death experiences at face value, 793 00:42:02,386 --> 00:42:07,380 then they suggest that the mind or the consciousness 794 00:42:07,458 --> 00:42:10,586 seems to function without the physical body. 795 00:42:10,661 --> 00:42:12,595 Dr. Hameroff: I think the quantum approach 796 00:42:12,663 --> 00:42:14,290 to consciousness can, in principle, 797 00:42:14,365 --> 00:42:17,926 explain why we're here and what our purpose is 798 00:42:18,002 --> 00:42:21,494 and also the possibility of life after death and reincarnation 799 00:42:21,572 --> 00:42:23,767 and the persistence of consciousness 800 00:42:23,841 --> 00:42:25,502 after our bodies give up. 801 00:42:25,576 --> 00:42:30,878 Dr. Alexander: I have great belief and knowledge 802 00:42:30,948 --> 00:42:33,974 that there is a wonderful existence 803 00:42:34,051 --> 00:42:37,248 for our souls outside of this earthly realm, 804 00:42:37,321 --> 00:42:41,052 and that is our true reality. 805 00:42:41,125 --> 00:42:45,221 And we all find that out when we leave this earth. 806 00:42:45,296 --> 00:42:49,096 Ultimately, every one of us will discover the truth. 807 00:42:49,166 --> 00:42:52,863 But will we ever enter our final hour 808 00:42:52,937 --> 00:42:56,395 knowing our fate? 809 00:42:56,473 --> 00:43:00,273 Perhaps some things really are too big for humans to grasp. 810 00:43:00,344 --> 00:43:04,678 That's when we have to shift from what we know 811 00:43:04,748 --> 00:43:06,943 to what we believe.