The Future of the Mind (55 page)

THE QUANTUM BRAIN

This debate also affects the reverse engineering of the brain. If you can successfully reverse engineer a brain made of transistors, this success implies
that the brain is deterministic and predictable. Ask it any question and it repeats the exact same answer. Computers are deterministic in this way, since they always give the same answer for any question.

So it seems we have a problem. On one hand, quantum mechanics and chaos theory claim that the universe is not predictable, and therefore, free will seems to exist. But a reverse-engineered brain, made of transistors, would by definition be predictable. Since the reverse-engineered brain is theoretically identical to a living brain, then the human brain is also deterministic and there is no free will. Clearly, this contradicts the first statement.

A minority of scientists claim that you cannot authentically reverse engineer the brain, or ever create a true thinking machine, because of the quantum theory. The brain, they argue, is a quantum device, not just a collection of transistors. Hence this project is doomed to fail. In this camp is Oxford physicist Dr. Roger Penrose, an authority on Einstein’s theory of relativity, who claims that it is quantum processes that may account for the consciousness of the human brain. Penrose starts by saying that mathematician Kurt Gödel has proven that arithmetic is incomplete; that is, that there are true statements in arithmetic that cannot be proven using the axioms of arithmetic. Similarly, not only is mathematics incomplete, but so is physics. He concludes by stating that the brain is basically a quantum mechanical device and there are problems that no machine can solve because of Gödel’s incompleteness theorem. Humans, however, can make sense of these conundrums using intuition.

Similarly, the reverse-engineered brain, no matter how complex, is still a collection of transistors and wires. In such a deterministic system, you can accurately predict its future behavior because the laws of motion are well known. In a quantum system, however, the system is inherently unpredictable. All you can calculate are the chances that something will occur, because of the uncertainty principle.

If it turns out that the reverse-engineered brain cannot reproduce human behavior, then scientists may be forced to admit that there are unpredictable forces at work (i.e., quantum effects inside the brain). Dr. Penrose argues that inside the neuron there are tiny structures, called microtubules, where quantum processes dominate.

At present, there is no consensus on this problem. Judging from the reaction to Penrose’s idea when it was first proposed, it would be safe to say that most of the scientific community is skeptical of his approach. Science,
however, is never conducted as a popularity contest, but instead advances through testable, reproducible, and falsifiable theories.

For my own part, I believe transistors cannot truly model all the behaviors of neurons, which carry out both analog and digital calculations. We know that neurons are messy. They can leak, misfire, age, die, and are sensitive to the environment. To me, this suggests that a collection of transistors can only approximately model the behavior of neurons. For example, we saw earlier, in discussing the physics of the brain, that if the axon of the neuron becomes thinner, then it begins to leak and also does not carry out chemical reactions that well. Some of this leakage and these misfires will be due to quantum effects. As you try to imagine neurons that are thinner, denser, and faster, quantum effects become more obvious. This means that even for normal neurons there are problems of leakage and instabilities, and these problems exist both classically and quantum mechanically.

In conclusion, a reverse-engineered robot will give a good but not perfect approximation of the human brain. Unlike Penrose, I think it is possible to create a deterministic robot out of transistors that gives the appearance of consciousness, but without any free will. It will pass the Turing test. But I think there will be differences between such a robot and humans due to these tiny quantum effects.

Ultimately, I think free will probably does exist, but it is not the free will envisioned by rugged individualists who claim they are complete masters of their fate. The brain is influenced by thousands of unconscious factors that predispose us to make certain choices ahead of time, even if we think we made them ourselves. This does not necessarily mean that we are actors in a film that can be rewound anytime. The end of the movie hasn’t been written yet, so strict determinism is destroyed by a subtle combination of quantum effects and chaos theory. In the end, we are still masters of our destiny.

NOTES

INTRODUCTION

1
You may have to travel:
To see this, define “complex” in terms of the total amount of information that can be stored. The closest rival to the brain might be the information contained within our DNA. There are three billion base pairs in our DNA, each one containing one of four nucleic acids, labeled A,T,C,G. Therefore the total amount of information we can store in our DNA is four raised to the three-billionth power. But the brain can store much more information among its one hundred billion neurons, which can either fire or not fire. Hence, there are two raised to the one-hundred-billionth power possible initial states of the human brain. But while DNA is static, the states of the brain change every few milliseconds. A simple thought may contain one hundred generations of neural firings. Hence, there are two raised to one hundred billion, all raised to the hundredth power, possible thoughts contained in one hundred generations. But our brains are continually firing, day and night, ceaselessly computing. Therefore the total number of thoughts possible within N generations is two raised to the one-hundred-billionth power, all raised to the Nth power, which is truly astronomical. Therefore the amount of information that we can store in our brains far exceeds the information stored within our DNA by a wide margin. In fact, it is the largest amount of information that we can store in our solar system, and even possibly in our sector of the Milky Way galaxy.

2
“The most valuable insights”:
Boleyn-Fitzgerald, p. 89.

3
“All of these questions that philosophers”:
Boleyn-Fitzgerald, p. 137.

CHAPTER 1: UNLOCKING THE MIND

1
He was semiconscious for weeks:
See Sweeney, pp. 207–8.

2
Dr. John Harlow, the doctor who treated:
Carter, p. 24.

3
In the year A.D. 43, records show:
Horstman, p. 87.

4
“It was like … standing in the doorway”:
Carter, p. 28.

5
The Transparent Brain:
New York Times
, April 10, 2013, p. 1.

6
“Emotions are not feelings at all”:
Carter, p. 83.

7
the mind is more like a “society of minds”:
Interview with Dr. Minsky for the BBC-TV series
Visions of the Future
, February 2007. Also, interview for
Science Fantastic
national radio broadcast, November 2009.

8
consciousness was like a storm raging:
Interview with Dr. Pinker in September 2003 for
Exploration
national radio broadcast.

9
“the intuitive feeling we have”:
Pinker, “The Riddle of Knowing You’re Here,” in
Your Brain: A User’s Guide
(New York: Time Inc. Specials, 2011).

10
Consciousness turns out to consist of:
Boleyn-Fitzgerald, p. 111.

11
“indeed a conscious system in its own right”:
Carter, p. 52.

12
I asked him how experiments:
Interview with Dr. Michael Gazzaniga in September 2012 for
Science Fantastic
national radio broadcast.

13
“The possible implications of this”:
Carter, p. 53.

14
“If that person dies, what happens?”:
Boleyn-Fitzgerald, p. 119.

15
a young king who inherits:
Interview with Dr. David Eagleman in May 2012 for
Science Fantastic
national radio broadcast.

16
“people named Denise or Dennis”:
Eagleman, p. 63.

17
“at least 15% of human females”:
Eagleman, p. 43.

CHAPTER 2: CONSCIOUSNESS—A PHYSICIST’S VIEWPOINT

1
“We cannot see ultraviolet light”:
Pinker,
How the Mind Works
, pp. 561–65.

2
“Everybody knows what consciousness is”:
Biological Bulletin
215, no. 3 (December 2008): 216.

3
We will do so in the notes:
Level II consciousness can be counted by listing the total number of distinct feedback loops when an animal interacts with members of its species. As a rough guess, Level II consciousness can be approximated by multiplying the number of others in an animal’s pack or tribe, multiplied by the total number of distinct emotions or gestures it uses to communicate with others. There are caveats to this ranking, however, since this is just a first guess.
   For example, animals like the wildcat are social, but they are also solitary hunters, so it appears as if the number of animals in its pack is one. But that is true only when it is hunting. When it is time to reproduce, wildcats engage in complex mating rituals, so its Level II consciousness must take this into account.
   Furthermore, when female wildcats give birth to litters of kittens, which have to be nursed and fed, the number of social interactions increases as a consequence. So even for solitary hunters, the number of members of its species that it interacts with is not one, and the total number of distinct feedback loops can be quite large.
   Also, if the number of wolves in the pack decreases, then it appears as if its Level II number decreases correspondingly. To account for this, we have to introduce the concept of an average Level II number that is common for the entire species, as well as a specific Level II consciousness for an individual animal.
   
The average Level II number for a given species does not change if the pack gets smaller, because it is common for the entire species, but the individual Level II number (because it measures individual mental activity and consciousness) does change.
   When applied to humans, the average Level II number must take into account the Dunbar number, which is 150, and represents roughly the number of people in our social grouping that we can keep track of. So the Level II number for humans as a species would be the total number of distinct emotions and gestures we use to communicate, multiplied by the Dunbar number of 150. (Individuals can have different levels of Level II consciousness, since their circle of friends and the ways they interact with them can vary considerably.)
   We should also note that certain Level I organisms (like insects and reptiles) can exhibit social behaviors. Ants, when they bump into one another, exchange information via chemical scents, and bees dance to communicate the location of flower beds. Reptiles even have a primitive limbic system. But in the main, they do not exhibit emotions.

4
“The difference between man”:
Gazzaniga, p. 27.

5
“The greatest achievement of the human brain”:
Gilbert, p. 5.

6
“area 10 (the internal granular layer IV)”:
Gazzaniga, p. 20.

7
The male gets confused, because it wants:
Eagleman, p. 144.

8
“I predict that mirror neurons”:
Brockman, p. xiii.

9
Biologist Carl Zimmer writes:
Bloom, p. 51.

10
“Most of the time we daydream”:
Bloom, p. 51.

11
I asked one person who may:
Interview with Dr. Michael Gazzaniga in September 2012 for
Science Fantastic
national radio broadcast.

12
“It is the left hemisphere”:
Gazzaniga, p. 85.

CHAPTER 3: TELEPATHY—A PENNY FOR YOUR THOUGHTS

1
Indeed, in a recent “Next 5 in 5”:
http://www.ibm.com/5in5
.

2
I had the pleasure of touring:
Interview with Dr. Gallant on July 11, 2012, at the University of California, Berkeley. Also, interview with Dr. Gallant on
Science Fantastic
for national radio, July 2012.

3
“This is a major leap forward”:
Berkeleyan Newsletter, September 22, 2011,
http://newscenter.berkeley.edu/2011/09/22/brain-movies
.

4
“If you take 200 voxels”:
Brockman, p. 236.

5
Dr. Brian Pasley and his colleagues:
Visit to Dr. Pasley’s laboratory on July 11, 2012, at the University of California, Berkeley.

6
Similar results were obtained:
The Brain Institute, University of Utah, Salt Lake City,
http://brain.utah.edu
.

7
This could have applications for artists:
http://io9/543338/a-device-that-lets-io9.com/543338/a-device-that-lets-ou-type-with-your-mind
.

8
According to their officials:
http://news.discovery.com/tech/type-with-your-mind-110309.html
.

9
being explored by Dr. David Poeppel:
Discover Magazine Presents the Brain
, Spring 2012, p. 43.

10
In 1993 in Germany:
Scientific American
, November 2008, p. 68.

11
The only justification for its existence:
Garreau, pp. 23–24.

12
I once had lunch with:
Symposium on the future of science sponsored by the Science
Fiction Channel at the Chabot Pace and Science Center, Oakland, California, in May 2004.