By PT Staff, published on January 1, 1996 - last reviewed on January 23, 2015
PT: You've been most associated with issues of outer space. But you
haveturned very much to a world of inner space, the human mind.
CS: Well, the boundary between space and the earth is purely
arbitrary. And I'll probably always be interested in this plan-et--it's
my favorite. I've written a number of books that have to do with the
evolution of humans, human intelligence, human emotions. So it isn't a
new departure for me to be concentrating on humans. Most of the people
that I deal with are human. So I've had a lot of experience with
PT: Some of your best friends are humans. Your new book, The
Demon-Haunted World, seems at times a litany of how the mind is fooled:
by its own memory, by its senses, by shoddy reasoning. Is there
intelligent life on Earth?
CS: Well, sure. But our intelligence is limited, and who would have
expected otherwise? We're imperfect, and wisdom and prudence lie in
understanding our imperfections. If we ignore our imperfections on the
grounds that it's too depressing to concentrate on them, then we greatly
limit our future options. On the other hand, if we know where our
limitations are, not just in thinking but in emotional things, if we know
about any hereditary predispositions we have towards ethnocentrism,
xenophobia, dominance hierarchies, then we have a chance to moderate
those tendencies. If we ignore any genetic predispositions in those
directions, then we don't make any serious effort to ameliorate them and
we're in much worse shape. This is one of those issues that every
generation has to learn anew, because every generation has the same
PT: But some of the issues you address in the book seem especially
endemic to present times: UFOs, repressed memory. Are these kinds of
things cropping up now more than before, as we approach the
CS: No. If you concentrate on the first few centuries of the
Christian era, let's say, or the time of Mesmer in France, or almost any
time in human history, you find just as many examples as from our present
time. This is an endemic human characteristic--to be credulous, to
believe what others tell us, to prefer what feels good to what's
PT: But until now, we've never been able to blow ourselves up . .
CS: Quite right. The dangers of not thinking clearly are much
greater now than ever before. It's not that there's something new in our
way of thinking, it's that credulous and confused thinking can be much
more lethal in ways it was never before.
PT: You point to the statistical likelihood of people in power
periodically showing up in the guise of a Stalin or a Hitler. Given this
probability, and given nuclear proliferation, what are your feelings
about the future?
CS: Well, it's a very serious issue. We are, fortunately, in a time
when the United States and the former Soviet Union are divesting their
nuclear arsenals. According to the present treaties, agreed to if not
ratified, each side will go down to something like 3,000 strategic
weapons and delivery systems by the first decade of the 21st century,
from 10 times that number. So that's very good news. On the other hand,
there are only about 2,300 cities on the planet, so if each side gets
3,000 weapons, that means that each side retains the ability to
annihilate every city on earth. That is certainly not comfortable news,
because if you wait long enough you are bound to have a madman at the
helm in one of these countries.
PT: Are you saying it's inevitable?
CS: If you look at the history of the world, such people regularly
come to power. We may comfort ourselves in the United States that it
hasn't happened to us, but even here I would say that a number of times
in our recent history we've come dose to having somebody dangerously
incompetent or drunk or crazy in power in a time of crisis. Hitler and
Stalin are reminders that the most advanced countries on earth can have
PT: You spend a good deal of The Demon-Haunted World talking about,
to use your term, scientific illiteracy. What do you think we should do?
Clearly everything is going in the wrong direction.
CS: Well, the first thing I would say is that every generation has
bemoaned the supposed lack of education of the next generation, and that
goes back to some of the earliest Sumerian tablets that we have, from
about 5000 years ago.
PT: With elders complaining about the youngsters of the
CS: Right: "They're not nearly as sharp as they were in my
generation. They're not motivated. They don't do homework." So, there's
always a danger of crotchety, elderly people comparing their generation
with youngsters and concluding their generation was much harder working,
more serious, had better values, better music, and so on.
Nevertheless, it's dear that there's a rampant dumbing down in
progress in which not knowing things is considered a virtue and in which
knowing things is considered a cause for embarrassment. I don't throw up
my hands in despair. But I do try to indicate that it's a very serious
problem that has no single point to face.
It isn't that if you were merely to increase the salaries of
schoolteachers, you would solve the problem. The problem is endemic. It
works at every level. It works in the culture of children themselves. It
works in the federal, state, and local government. It works in the media.
It works in the school boards and taxpayers with school bond issues.
There's not just one point of attack. And it's very hard to imagine a
serious change unless there's a change of behavior at many levels by many
different people. That involves rethinking, it involves changes in
values, it involves money--not out of cynicism, but out of understanding
how the real world works. It's going to be very difficult to make this
change unless, as happened with Sputnik, there's an apparent threat to
national security that requires us to learn more science.
PT: We need a Sputnik-like explosion in public awareness to make us
think, wake up.
CS: We do have the example of the late '50s and the early '60s. I
don't know if that's the only thing that can make us do it. A sudden
outbreak of wisdom maybe would be such a shock.
PT: I don't think we should count on that. Sputnik worked in part,
I think, because people then had faith that science was going to cure our
medical ills and solve the world's problems. People today don't have the
same view of science as a panacea.
CS: As someone whose life was saved in the last six months by
medical science, I certainly don't share the skepticism. The lives of
almost everybody on earth depend in the most intimate way on science and
technology--to be unenthusiastic about science and technology is not just
foolish, it's suicidal.
Without agricultural technology, for example, the earth could
support only tens of millions of people, instead of billions. That means
that almost everyone on earth, 99 percent of us, owe the very fact that
we're alive and haven't starved to death to the existence of
PT: You just referred to your own intimations of mortality. Has
that changed your outlook at all? You've recovered from something that
could have been very serious.
CS: It was very serious. It's a bone marrow disease called
myelodysplasia, which is invariably fatal if not treated. I had a bone
marrow transplant at the Fred Hutchinson Cancer Research Center in
Seattle. I was lucky that my only sibling, my sister, was a perfect
match. It was lucky, but also I was the beneficiary of decades of
experience that that institution, and medical science in general, has had
in bone marrow transplants. The age at which you can get a transplant is
increasing every year. I think I'm the oldest person to get a
PT: Science saved your life.
CS: This is not the first time I almost died. This is my third time
having to deal with intimations of mortality. And every time it's a
character-building experience. You get a much clearer perspective on
what's important and what isn't, the preciousness and beauty of life, and
the importance of family and of trying to safeguard a future worthy of
our children. I would recommend almost dying to everybody. I think it's
really a good experience.
PT: Probably once is enough for most people. In part because
science has done such a wonderful job of saving lives, we have a
population crisis, at least in some people's eyes. Does that worry
CS: Oh yes, absolutely. But it's also clear how to resolve the
problem. It involves complex social issues, and there are religious and
nationalistic objections to dealing with the crisis. As with all crises,
it will, if untreated, blow up in our face. The way to treat it is very
threatening, since it is the billion poorest people who reproduce
fastest, for simple reasons of survival. If you have children and no
Social Security, there's a chance that some of your children might
survive into your old age and take care of you. It's a simple calculation
that the poorest people make, to have lots of children. So the first
thing to do is to improve the self-sufficiency of the billion poorest
people on the planet, which will lessen the charity of the major
religions, It's not just good ethics, it's good in the most practical
There also has to be a ready supply of safe, easy-to-use
contraceptives. And the third key item is the political empowerment of
women. There are societies in which the per capita income is high, but
women are so oppressed that they cannot have a say in whether or not they
have children. There are good reasons for helping the poorest people, and
good reasons for empowering women, apart from the population crisis. But
the population crisis makes it very dear that those should be prime
PT: You're not just a scientist, you are also a celebrity. Because
of that visibility you can be a salesman for certain issues if you care
CS: Since childhood, the most pleasurable occupation I could
imagine was being a scientist. It had a romance to it that nothing else I
know of even approached. And I've never lost that. My goal always was to
be just a working scientist. It's true I studied some very exotic areas
of science. I was interested in exploring other planets at a time when
man had not even gotten outside the earth's atmosphere. So I actually
have spent much of the last 35 years exploring the solar system my
But, at the same time, I'm a citizen, a parent, a grandparent. I'm
concerned about the future for all sorts of readily understandable
mammalian reasons, and I would much rather work hard to make a better
future, even if I fail, than to make no attempt.
PT: Do you spend half your time doing research and the other half
doing soldier's duty as one of the world's most famous scientists?
CS: I don't try to budget my time from one to the other. They sort
of naturally flow into one another. For example, I did my doctoral thesis
on the Venus greenhouse effect, never imagining that the greenhouse
effect would be a major global policy issue 30 years later.
There are several other cases--nuclear winter is one--in which the
science and the public policy effortlessly flowed into each other. And
the most natural thing in the world, if you find a science that you're to
some degree expert in, is speaking out about a danger to the global
civilization of the human species. If you won't, who's going to speak
out? I just don't see it as two hermetically sealed compartments that you
hop from one to the other. It often just flows in the most natural
I do have an opportunity that, unfortunately, others who are
equally or more capable sometimes don't have, of communicating to the
general public. And it's an opportunity that ought to be used carefully,
not squandered. And used responsibly. But if I have opportunities to
speak to the public, then certainly I'm not going to say no if I have
something to speak for.
PT: Do you still have the same sense of wonder over science as you
did 25 years ago?
CS: Last week, a planet seems to have been discovered around a
nearby star called 51 Pegasus. And it's a planet very close to the star,
much closer than Mercury is to our Sun. But it's not a little rocky world
like Mercury or Venus or the earth. It's a giant world, presumably like
What is such a massive planet doing so dose to that star? Does it
have other terrestrial-type planets further out? Is that planet a gas
giant the way Jupiter is, or is it a monster Earthlike planet? And what
does it say about the abundance of planetary systems elsewhere? Maybe
they're all like that, and ours is anomalous. If that's true, what
implications does that have for the origins of solar systems? I don't
know. My wonder button got pushed hard when that discovery was announced.
And it happens regularly. It certainly happens in my own research, such
as in the laboratory work that we do on organic chemistry and the outer
solar system, the origin of life on earth. My wonder button is being
pushed all the time.
PT: When you look at fellow scientists who are not, say, 25 or 30
anymore, do they still have the ability to wonder?
CS: Some do, some don't. Some lose it.
PT: What makes it go?
CS: One thing is a kind of Peter Principle. Good scientists are
eventually offered opportunities to be administrators. That takes them
away from science. To be the department chairman, the president of a
professional society, or a presidential science advisor, or
whatever--those are all responsible and important positions, even ones
that can aid the advancement of science. But not by you doing the science
yourself. It's very hard to continue doing the science in some of those
positions. They are very time consuming. So that's one danger. Another
thing is, the wonder is almost instinctive--you can see it in
children--but the skepticism has to be learned. And you learn it
sometimes by painful experience. You have experience with baloney, so
your baloney-detection ability improves. If you never encounter baloney,
then there you are, with all wonder and no skepticism.
So as time goes on there's a tendency to become more and more
skeptical and to mistrust wonder. Very dangerous, because it's the
balance between the two that's needed. So in a lot of scientists, the
ratio of wonder to skepticism declines in time. That may be connected
with the fact that in some fields--mathematics, physics, some others-the
great discoveries are almost entirely made by youngsters.
PT: Was Einstein at the end of his life a man who had the capacity
CS: No question about it, absolutely full of wonder.
PT: You've said that when you were growing up you didn't realize
somebody could do science for a living. You envisioned being a salesman
or something and doing science on weekends and evenings. It's all too
rare that someone as young as you were at the time becomes so enthralled
with science. Are we essentially killing off the wonder in
CS: Every kid starts out as a natural-born scientist, and then we
beat it out of them. A few trickle through the system with their wonder
and enthusiasm for science intact. PT: Why did yours stay intact?
CS: The main thing was that my parents, who knew nothing about
science, encouraged it. They never said, "All in all, wouldn't it be
better to be a lawyer or a doctor?" I never once heard that from my
parents. They said, "If you're passionate about that, we'll back you to
the best of our ability." In school, while there were very few teachers
who excited me about science, there was no systematic effort to
So it wasn't that hard to maintain my interest. Science fiction
sustained me in my earliest years. I got a keen sense of the excitement
of science from science fiction.
PT: What is the dumbest thing you've ever done? I mean that
CS: Oh, there are so many competing candidates. In fact, in this
book I list some of the times where I've been dead wrong; in past books
I've tended to stress the cases where I've been right, like the
greenhouse effect. I suppose that's a natural humaning, but I've tried to
make up for it a bit. Mistakes, wrong guesses, invalid conclusions are
not disasters in science. In many cases they spur others to disprove or
to check you out. And so it advances the field. The greatest scientists
have made mistakes.
But one of the beauties of science is that it has built-in
error-correcting machinery. Science, unlike many other human endeavors,
reserves its highest rewards for those who disprove the contentions of
its most revered leaders. Think, for example, of religion. How foreign
that scientific point of view is from the religious idea, which so often
is to uncritically accept whatever the founder of the religion said. It's
not a tragedy that scientists make mistakes, and I certainly have made
some in my time.
PT: Coming as you do from a hard-science background, how do you
think psychology is doing as a field? A lot of the issues in your book
are big areas in psychology.
CS: I'm not a psychologist. I don't have a comprehensive
surveillance of the whole field, so all I can do is give you an offhand
The thing I've been most appalled by is the sense of so many
psychotherapists . . . that their job is to confirm their patients'
delusions rather than help them find out what really has happened. It
took a long time to convince myself that's what's happening, but it
certainly is happening. I don't know whether it's more likely among
social workers than Ph.D.s in psychology, or more likely among the Ph.D.s
than the psychiatrists, who have medical training. But I do find it
astonishing that anybody in psychology should be ignorant of the most
elementary precepts of skeptical scientific scrutiny.
As someone who spent a lot of time reading Freud and his followers,
I also am distressed by the absence of a systematic effort to demonstrate
that psychoanalysis is more useful than going to your priest or rabbi. Or
whether there is such a thing as repression. It's always very dangerous
when the error-correcting machinery is not working and there aren't
systematic attempts to disprove what the revered founder of your field
On the other hand, I see spectacular potential in imaging analysis
of brain function. That is an amazing development, and you can see really
major understandings of brain function coming out of that. Also
tremendous]y exciting is the work on neurotransmitters, work on
endorphins, and on the small brain proteins. Those are all tremendously
exciting, and all of them, by the way, tend to support the idea that the
mind is merely what the brain does. There's nothing else, there's no soul
or psyche that's not made out of matter, that isn't a function of 10 to
the 14th synapses in the brain.
PT: As someone who has argued so eloquently about the role of
evidence in making decisions, what is your reaction as a citizen and
scientist to the O.J. trial?
CS: There are a lot of studies of juries that suggest that people
make up their minds in the opening arguments, selectively remember the
evidence that supports their initial judgment, then simply reject the
contrary evidence, put it out of their heads. I suspect that did happen
The fault lies with prosecutors for relying on complex scientific
and mathematical arguments without explaining it in a way the average
person can understand. It was a failure to understand what is necessary
in talking to the public about science. When we hear that the chance of
this blood being someone other than O.J. Simpson's is one in 100 billion,
and there are only 5.5 billion people on the planet, and that is intended
as a knock-out punch . . . . If somebody has no knowledge of elementary
probability theory, the prosecution has an obligation to explain it step
by step, from there being one chance in two when flipping coins, to
highly improbable events.
Likewise, I think many jurors, many Americans anywhere, have little
sense of what DNA is. They need some background on what DNA is, what are
its unique characteristics, why it is different from person to person,
the role it plays in determining heredity. There was none of that.
PT: Can that be accomplished in a trial?
CS: Sure. You do it in a very effective, humorous way with
excellent visuals. It's pointless to bring to the public scientific and
mathematical evidence if no one going to understand what you're
PT: You've done that as well as anyone.
CS: I'm often asked by colleagues what's the secret. Many
scientists who are superb practitioners of their field claim that they're
no good at explaining science, but I just don't believe that. I think
there's only one secret. And that is, Don't talk jargon. Don't talk as
you would to colleagues. Instead, talk as you did to yourself at the time
when you yourself didn't understand. You have to explain to people what's
true in ordinary language, not technical terms. You have to respect the
intelligence of your audience, but remember that they haven't had the
advantage of the same technical education that you have.
PT: In looking for intelligence and originality in people, what
earmarks do you use?
CS: I look for enthusiasm and wonder, but there's such a thing as
too much. I look for someone who knows what he or she is talking about,
because there's a tendency to repeat anything you've read without
skeptical scrutiny of it. But in meeting people, it's rare that what I'm
impressed by is their intelligence. There's much more likelihood that
what I'm impressed by is their compassion, their optimism, their sense of
humor-things of that sort I find much more compelling. There are very few
people who don't have an impressive degree of intelligence, especially
children. Society does very dangerous things in squashing that
intelligence. It's a tragedy. You can see a kind of Darwinian competition
of nations, and the ones that squash the intelligence of the citizenry in
the long run are not going to do very well. The ones that learn to
encourage curiosity and wonder and hard work are the ones tt}at are going
to make it.
PT: Are there insights to be gained from nonrational thought,
CS: Certainly the insight that we're capable of nonrational thought
is to be gained from nonrational thought. That is something very
important. Every society--there are no exceptions--has some kind of
religion. That tells us something important about human nature. It
doesn't say that what the religion says is true. It says that there is a
common need, that must be genetically based, that religions make an
effort, successful or not, to deal with.
PT: A drive to find meaning or purpose?
CS: It's partly that, and also the need to have a code of ethics,
because otherwise society is impossible. A sense of community, communion
with nature, communion with your fellow human beings. A sense of ritual,
music, art, poetry. Religion appeals on many different levels and serves
many different needs. It would have to, to be so widespread.
PT: You have a young son. What are your biggest fears for the world
CS: There are so many. I'm certainly worried about local and global
environment. About overpopulation and violence. I'm worried about
stupidity. I'm worried about consumerism, the focus on buying things that
by any survival standard you don't need, but which American advertising
culture promotes like mad.
PT: What gets you most excited for him?
CS: The inexhaustible benefits that emerge from science. I don't
just mean agriculture and medicine, which have a large variety of
practical benefits. The thing I like most about science is its room for
managing the future. It's a tool for baloney detection. It's absolutely
essential, not just for the technological products of science, but as a
way of thinking. If that were more widely understood, we'd be a lot more
secure in the future than we are now.
PT: Aldous Huxley wrote Brave New World in 1932. Have you thought
of writing a book about the future, say, a century later?
CS: Prophesy is a lost art.
PT: He didn't write a prophesy, he just took information--
CS: Well, more than that. He was trying to give us a glimpse of a
future society we should avoid. It was a cautionary tale. That was one,
but there are so many. There are already possible dire futures; you could
spend the rest of your life writing cautionary tales. Anyway, I have no
plans to do so.
PT: You did write a novel a few years ago. What inspired you to
CS: It's called Contact. It's being made into a motion picture
starring Jodie Foster. It's the story of the receipt of a first bona fide
radio message from another civilization in space, and of the response
here on Earth, which is very complex and diverse. I wrote it because it
was an opportunity to get across scientific ideas to an audience
different from that of Scientific American.
Also, it seemed fun to try to write fiction. And many people have
asked me what I think the consequences of receiving such a message would
be. I never could give in a few sentences what seemed to me an adequate
PT: Are you hopeful that there is intelligent life
CS: My mind is certainly moot. Monitoring extraterrestrial radio
waves is a chance, at relatively small cost, to try to answer one of the
deepest questions ever posed. It's the importance of the quest, and the
fact that we don't know enough to say in advance that it's fruitless,
that motivates me. But I don't pretend to know that there are beings out
PHOTO (BLACK & WHITE): A Slayer of Demons
Turning from outer space to inner sapce, Carl Sagan wants to know
one thing: Why is it that we prefer what feels good to what's true? He
stands tall for our natural sense of wonder-- balanced by
baloney-detection skills. Sagan sees our national inability to translate
science coming back to haunt us in, say the O.J. verdict.
PHOTO (BLACK & WHITE): Carl Sagan