David Albert, John Horgan, Kelly Moore, Robert Park

: Steven Jay Gould sent a letter to Science a few years ago about the motto of the Royal Society, nullius in verba -- or, as it's usually translated out of context, "nothing in words," which, to a lot of scientists, encodes the idea that words can't be trusted but facts and quantitative things can. Gould pointed out that when you take the phrase nullius in verba in its fuller context from Horace, it wasn't saying "nothing in words." It was saying "I am not bound to swear allegiance to the word of any master." It's nullius in verba... magistri. It has to do with scientists' being free from political authority, not from language. With that in mind, what would everyone have to say about that distinction between objective fact and the non-objective perspectives people bring to their apprehension of fact?

Horgan: There's some proportionality between the lack of scientific substance of a field and the degree to which its most successful participants are good rhetoricians. For example, in evolutionary biology at this point, all of the really prominent people are great writers -- Gould, Dawkins, E. O. Wilson -- and that makes me suspicious that they're not really getting at something important scientifically, issues that can be empirically resolved, as opposed to fields like molecular biology and nuclear physics where rhetoric is pretty much irrelevant.

Park: But isn't that because of the peculiar situation that evolution finds itself in? It comes more directly into conflict with people's belief systems, and I think that's why they elevate their spokesmen. They seek out those who can really get out there and spread the word. Dawkins is not famous because he's made enormous strides in evolutionary knowledge, so much as he has enunciated clearly what everybody was doing. Evolution has just made incredible progress in being able to explain the details.

Albert: I guess I disagree with [John's] conjecture as a general point. I think there are moments in the histories of various sciences when it's necessary to engage basic philosophical questions that have been important to the culture in other ways. There are other moments in the history of any particular science (in Kuhnian terms, a "normal science" phase) where there are explicitly mathematizable problems to be worked out. That's the task of the field at that point, and you're less likely to see people engaged in philosophical discourse or the valorization of rhetorical skills. But it was crucial to the success of the Scientific Revolution, I think, that Galileo was one of the best writers of the Italian Renaissance.

Horgan: Rhetoric is obviously important, but what distinguishes a theory of astronomy from Marxism, for example? Marx was a great rhetorician and writer, but at this point I don't think anybody considers Marxism scientific. (Maybe at Columbia they do.)

Albert: I don't think there are that many examples of nineteenth-century sciences that haven't suffered some significant kind of revision or revolution since then.

Moore: I agree with that. I would also say that Marxism does have propositions that can be either empirically verified or not: one could test whether divisions in people's relative levels of income are getting greater, or staying the same or getting smaller, as Marx would have predicted. Many fields have mathematically testable hypotheses, but only fields with considerable consensus about the nature of their subjects and methods typically rely heavily on mathematics. But scientists in all fields use words -- often eloquently and movingly, as in physicists' writings after World War II about the ethical and moral ramifications of the atomic bomb -- to resolve crises about the fundamental nature of their subjects and humans' relationships to these subjects.

Horgan: When scientists are talking about whether nuclear weapons are bad or good, that's a moral issue. It's not an empirical issue that can be resolved through scientific methods.

Park: It's not their science they're arguing about.

Horgan: Moral issues are really opinions. They are not scientific statements that can be resolved through experimentation or logic and reasoning.

Moore: Agreed. But you're suspicious of evolutionary biologists because some of them in the public eye write so well. I'm not suspicious about evolutionary biologists because of that. I would say that being a good writer, being able to communicate one's ideas to one's colleagues in a language other than mathematics, should be icing on the cake.

Horgan: I'm really just trying to find what distinguishes fields that make genuine progress from those that seem to be constantly spinning their wheels.

Albert: I think you have to distinguish between kinds of progress. There are parallels to the case of Galileo. In the beginning of this century, when physics was making breathtaking progress, its leading practitioners like Einstein and Bohr and Heisenberg were deeply involved in philosophical debates. Perhaps the most explicit case is Einstein, whose work on special relativity was profoundly influenced by his reading of Mach and his engagement with earlier philosophers of space and time, like Kant. It was crucial to the development of quantum mechanics that people like Bohr and Heisenberg had a deep intellectual engagement in certain philosophical debates about positivism, the independence of the external world from the act of observation, or its lack of independence from the act of observation.

Later on, once the foundations of quantum mechanics were in place, things turned around quite dramatically. You then had a situation where it was thought that the foundational questions about quantum mechanics were settled, and that the task before physics was now a more technical one of deciding what the correct Hamiltonian of the world was, of applying quantum mechanics to all sorts of other cases. In that atmosphere, philosophical engagement not only declined but became positively suspect.

Park: It got in the way.

Albert: Yes, that's right. It was widely thought that surrendering oneself to a certain kind of philosophical reflection was a way of spoiling the party, and in a very rear-guard way, being a nudnik when everybody was making spectacular progress applying quantum mechanics all over the place. So I think there are cycles in the history of science: one goes through eras characterized by more conceptually revolutionary sorts of developments, where people find it crucial to scientific progress to surrender themselves wholly to certain kinds of philosophical questions and debates where questions of rhetoric become more important. And there are other eras where that represents a more decadent or counterproductive or less valorized tendency.

Horgan: The way I distinguish between science and philosophy is that science addresses questions that can be answered eventually. Somehow, you get consensus. Philosophy addresses all the other questions that can't be answered.

Final goals or permanent process?

Horgan: There are two parts of my argument about the "end of science." The first question is "Is science in principle finite or infinite?" That's the question that's obsessed me for a long time. I think most people will grant me that science is finite, at least in the sense--

Park: Most physicists won't, I can tell you from experience.

Horgan: But a lot of physicists have this notion of the final theory. Stephen Hawking has talked about it, and Steven Weinberg.

Park: In your book you said that there are three ways it might come to an end. Either we're going to get the final theory, and that's what we're all working for, or it may turn out to be so huge, so complex, that the human brain cannot encompass it; the third way was that it's going to get so expensive that society won't pay for it. (That kind of "end to science" I understand perfectly.) I think there are some signs that we may be getting close to that in certain areas: the idea that there may be a final theory and there won't be any more huge breakthroughs. Most people in science are not working towards some huge paradigm shift; they're getting the next piece. So they don't feel like what they're doing is going to come to an end, and they're probably right. You can always make more measurements, get more detailed. But in terms of things that change in a fundamental way, the way we think about the universe and our place in it: I have faith that we will get to the end of that.

Moore: What is science? Science is a formalization of a very human activity that's been going on since human beings emerged: trying to understand the world around us, using our senses, in systematic and formalized ways. When you [Horgan] say "the end of physics," I can believe that there will be a point at which we cannot learn much more about very small particles and the early universe from logical, empirical, mathematical analysis. But does that mean we will abandon the possibility of addressing and understanding other kinds of questions which we now may think of as off limits morally, unscientific, or not amenable to that analysis? I don't. I'm optimistic about human beings' ability to be creative, to seek out and know new things, and to need to know more things. Most of what we know has been driven in part by curiosity, but also by human beings' needs to find out about the things around them, to protect themselves, to build communities that work. I believe that process will continue.

Horgan: Science in some form has got to continue. The question I'm trying to raise is "What's it going to give us?" Are we going to have discoveries as fundamental as the expansion of the universe, the basic big bang theory? It was an incredible thing to have learned. Now, how do you top that?

Park: You reconcile relativity and quantum mechanics, as an example.

Horgan: I think that's a false scientific problem. I think it's a problem arising out of an incompatibility of these mathematical formalisms. It's not a real problem.

Albert: Wait, wait. This is worth clarifying. I don't understand what you mean by an incompatibility of these mathematical formalisms. From what I understand, you're happy to say that quantum mechanics is a theory forced on us in a fairly compelling way by empirical experience, and general relativity is a theory forced on us in a fairly compelling way by empirical experience. We have two views about the world, which we're strongly committed to by empirical evidence, which turn out to conflict with one another. To say it's a conflict between the mathematical formalisms makes it sound much less threatening than it actually is. These aren't formalisms that came out of nowhere. These are formalisms to which we feel our empirical experience more or less directly commits us.

Horgan: The best postmodernist argument I've ever encountered is George Johnson's in Fire in the Mind. He talked about science as an historical process that has a lot of contingency built into it, and wondered how science could have evolved in different ways. You can ask what features of science are really robust and would have been discovered by almost any intelligent civilization. There are certain things like elements, atoms, stars, and galaxies that almost any creatures with sensory apparatus more or less like ours would have discovered. Those are discoveries. It gets more problematic when you're talking about Newton's version of gravity or quantum mechanics and general relativity. Are those really discoveries in the same sense?

Albert: Do you take quantum mechanics and general relativity to be among the pantheon of theories that belong to this good scientific tradition of theories that we're committed to as a fairly directly result of our empirical experience? You seem to grant that. There are zero steps left from that, because if those are among our solid empirical commitments, then there are contradictions among our solid empirical commitments, and there can't be contradictions in the actual empirical world.

Park: In the past, when we've come to these contradictions, it always meant that there was a big step we were about to take.

Forms of knowledge in a possibly lawful world

Albert: It's precisely the question of whether it is a fully lawful world that's at stake when a situation arises like a conflict between our empirical commitments to quantum mechanics and to general relativity. Steven Weinberg said that it will be a very important achievement of physics -- if it succeeds -- in providing some compelling demonstration that the world is lawful. That is, the fact of that having been demonstrated might overshadow, in philosophical importance, the facts about what particular laws it's being shown to obey. But it's the question of the possibility of subsuming the experience of the world to some mathematized, theoretical description that's at stake.

Horgan: But the irony is, the best reason he could come up with for trying to get the final theory was that then people wouldn't believe in astrology and ESP any more. Of course, Weinberg doesn't need superstring theory to rule out all that crap.

Park: But it's his aspiration that the public at large should begin to understand that they live in an orderly universe, and that they can't change the rules by piety or anything else. That's an important concept for people to have.

Horgan: If people aren't convinced by now that New Age claptrap is just that, they're never going to be. I think if you took Bohr, Einstein, or any late-nineteenth-century intellectual and brought him up to our era and showed the degree to which science has not taken hold in society, he would just be appalled. Superstition is obviously very deeply ingrained.

Park: It is a shock. I've got a chapter in my book entitled "The Belief Gene"; I think there's a real problem with the organism here.

Horgan: On the other hand, I don't think there's all that much difference between believing in astrology and believing in chaotic inflation or string theory. I'm sorry.

21stC: Here we're onto the territory where some postmodernists will say all these things involve leaps of faith; there are no grounds for saying any final theory is final; we don't necessarily live in a lawful universe; one discourse merely replaces another. There are people who recognize no grounds for a foundational belief in anything; they're taking their narratives from the New Age things that you've described as claptrap. A lot of people need to believe in these things, even though falsifying them is pretty easy to do. From everybody's perspective: why?

Park: Well, I listened to Paul Forman just two weeks ago. The point at which we got as far as we could on agreement was when Forman said there has been no scientific progress in the last 200 years, maybe not since Aristotle. He says "What do you mean by progress?" He questioned the whole existence of scientific progress.

Moore: Did you ask him what he meant by progress?

Park: We tried. There were lots of questions about what he meant by progress, and he would go back and he would say he was not sure that Kepler or Newton would see what has happened as progress, because Newton had some pretty strange ideas about religion too.

Horgan: He means progress in a moral sense?

Park: Progress is a word that scientists have trouble with, because they can't write an equation for progress. But if we cannot agree that there has been scientific progress, then I think there's not going to be an agreement.

Horgan: I never met any philosopher who actually said, "I don't believe in atoms and elements and viruses" -- they get playful and say things to irritate scientists, but they don't really mean that -- but Paul Feyerabend is probably as close to a real relativist as anybody, and he believed in science. He knew science is incredibly effective. It was precisely because he realized how powerful science is, as a mode of truth, that he thought it was important to criticize it and show its weaknesses. The questions he was raising were moral: Does science, just because it happens to be a real mode of knowledge, have the right to bully all the other pseudo-modes of knowledge like religion and astrology?

Albert: I don't know anybody who doesn't think the success of the scientific enterprise commands attention. But Feyerabend had epistemic questions to raise, not just moral questions, about science: questions about the extent to which we are ineluctably committed to scientific theories by our empirical experience. But I agree with you, I don't know of anyone in the field, including people involved in the recent "Science Wars" debates, whodoesn't agree that there is a spectacular story of the success of western science.

Moore: You mentioned two sorts of criteria for judging progress. One was about progress toward truth, and the other one had to do with the making of things, the ability to successfully predict something should happen. Those are two very different ways of thinking about what we mean by progress, and the awesome progress of science. There is nothing that has matched this particular method in its creation of goods that make human life better. I'm thrilled that there are polio vaccines and that I have a computer and that I'm going to live a long life, when I would have died many years ago from an illness, without having had medicine. That is untouched by any other way of thinking, in terms of this sort of outcome: the making of material things that have improved human life. However, when you say "truth," this opens up a huge can of worms. It gets back to your questions of meaning. I am not at all troubled by this question about why people appropriate the tools of science and -- A relative calls me on the telephone and says, "You're acting that way because you're a Taurus." [laughter] This is a person with advanced degrees, and what is she doing? And other people will have various other things that they have appropriated to create meaning in their lives and create something predictable for themselves.

Park: So let me just ask the straight question: Are there other ways of knowing, other than science?

Moore: Sure; if you're a yogi, you could say that you have a way of knowing/experiencing something. That is very different from saying that you know how to make a pen. It also has a different goal. A goal in science is to try to understand components of things, how things get put together, how they originated, very small systems, very large systems. For somebody who does yoga every day, that's a different way of experiencing things with a completely different goal, and I think that those are two reasonable and meaningful systems to have coexisting. So I think that there are "ways of knowing," but there are very different sorts of goals linked to different systems of knowing.

Park: Now we're talking about what we mean by knowing.

Reasons people look for knowledge

Horgan: I don't think yoga and religion are after knowledge. I don't see what the point of religion is, unless it's to make us feel better.

Moore: We all have belief systems. You may not call yours religion; you may not have it formalized. But there are things you take for granted on a daily basis. You also have things that are meaningful to you, without perhaps some rational basis. Perhaps you have a child; that has tremendous meaning to you. It doesn't have a rationalized basis. Human beings create meanings in their interactions with each other; I think that's partly what makes us human. I also think that science partly gives us meaning. Knowing where we came from, a scientific question -- understanding empirically, theoretically, the questions you're asking about -- has tremendous importance for us in terms of meaning.

Park: It seems to me that most of the serious problems we have as human beings arise from the belief that there are other ways of knowing -- that that's in fact where prejudice, religion, all these things come from, these narrow points of view that lead us into exactly the sort of problem that we have in race relations. These are because people think there are other ways of knowing. They have this feeling that "we guys are better than those guys."

Horgan: But science can also lead to scientism, where you think that science can just sweep away all problems in front of it, and should sweep away all other belief systems such as religion. Feyerabend would say, just because science is truer, just because the big bang theory is truer than the Christian version of creation, does that mean scientists have a right to destroy those other belief systems?

Park: Certainly not. However, they have a responsibility to explain the way the universe came about.

Horgan: It gets tricky when you're talking about what your kids are going to be able to learn in school.

Park: Of course, the problems are complicated. We evolved essentially unchanged from our Cro-Magnon ancestors, who were good at recognizing which log to turn over so that they can find the grubs underneath. That's the world we were evolved to live in. Evolution is a slow process, which by and large has come to a stop because of the intermixing of populations; you've got to isolate populations to get evolutionary progress. If you clone a Cro-Magnon and brought him here today, raised him in our society, he would be indistinguishable from the rest of us. We are living in a world we were not evolved to cope with; the amazing thing is that people are as relatively sane as we are. The wonder is that it doesn't drive us all nuts: that the same brain that enabled us to find the grubs and avoid the predators enables us to write sonnets or do integral calculus. It's really astonishing that that brain should be able to do that.

Horgan: I see a lot of what's happening in science now as an attempt to answer questions that can't be answered. Science has been very successful at mapping out reality from the microbe level all the way out to quasars, galaxies, and so forth. Now at the Santa Fe Institute they're trying to figure out how probable various features of reality are. If you've got a million universes, how many would have these particular laws of nature, or galaxies, or life like ours? It's the old idea of Einstein's: "How much choice did God have in making the universe?" To me, these questions are just not amenable to science. We only have one universe for comparisons.

Moore: I think that some of the most exciting research that's going on, that does seem to have answerable puzzles, is in biological science.

Park: They're on a roll.

Horgan: And in biology, I think this is where Gaia theory comes from. The strict theory of evolution makes life seem awfully tenuous; there doesn't seem to be any real reason why life had to be here. So you have Gaia, which is kind of group selection taken to some absurd extreme: "life had to grow because it's all interacting with some big teleological purpose in mind." It's the same with Stuart Kauffman at Santa Fe saying there are laws of complexity that have made the appearance of life and its subsequent evolution very probable -- and even the creation of intelligent beings like us. I think there's some kind of spiritual impulse behind this.

Albert: That sounds like a straightforward empirical claim, which is either true or false. It ought to be the paradigm of a good scientific claim.

Horgan: Yeah, but it's not very easy to resolve, for obvious reasons, purely physical limitations. If we invent warp-drive spaceships that allow us to zip through the universe and actually determine whether life is ubiquitous, and then we can compare different life systems, that will be a renaissance for biology. This is why I was hoping that the life-on-Mars thing was going to be real, because it would have been a tremendous new era of comparative biology. It would be cool if we found it here in the solar system, but it's most likely just going to be microbial.

Park: Well, SETI is about the only way we're going to find it beyond.

Horgan: What's interesting about SETI is that its hardcore proponents are all physicists, and physicists are deterministic. They think that because there's an intelligent civilization on Earth, there have to be intelligent civilizations elsewhere in the universe. But if you talk to Ernst Mayr or Steve Gould, they will say to you that that's completely random.

Park: It was only an accident that we had it here.

Horgan: That's right. If you reran the tape of life a million times over, you probably wouldn't even get mammals, let alone creatures intelligent enough to invent radio and television. So I think the outlook for detecting life elsewhere is dismal. Of course, if you believe in alien abductions, then that's not a problem.

21stC: Presumably we don't, but we inhabit a social body in which some people do. I'm still intrigued by how some beliefs coexist with others when they should be able to trump them on objective or rational grounds.

Park: You're getting back to my "belief gene"; did evolution somehow program human beings to believe? One can imagine various reasons why evolution would do that -- to confer courage in battle, or whatever.

21stC: To calm the mind that might otherwise drive us insane.

Moore: But you also are making an assumption that there is no way in which scientists also have faith in the other people doing the work with them. You don't know what your colleagues are doing all the time, right? You have to have some trust in what other people are doing. You can't go and verify everything perfectly. We know that things work well enough to make to make guns fire, to do other sorts of things, but to make the radical split, saying there are some things that are purely without faith behind them, seems to be a fairly absurd statement. Things have historical, cognitive, social, political, and economic contexts in which people make meaning. There's a continuum of people who use certain sorts of tools, from the most scientific and rational thinkers in our society to people at the other extreme, who never use those tools. But people in between use different combinations of those tools in different settings to understand different sorts of things. I don't see that as unreasonable.

Horgan: Science is not very nurturing. Some scientists have hoped that science would displace religion. I think the reason [it hasn't] is that science, unless you goose it up with all kinds of New Age stuff, is a very disturbing, cold world view. Steven Weinberg had this famous phrase -- "The more the universe becomes comprehensible, the more it becomes pointless" -- which I think is absolutely true.

Park: I think that's true, but I don't find that disturbing.

Horgan: But most people do, Bob. That's because you're a physicist. Most people find that intensely disturbing and that's why even very smart people, even physicists still believe in the Bible or in . . .

Moore: So that science can't answer all the questions human beings seem to find necessary to ponder: existential questions, things like why it feels good to get a hug from somebody.

Horgan: The classic religious question is, what's the universe here for? Is there some purpose to it? Religion says that there is a divine creator with a plan . . .

Moore: I think the answers will come not only from empirical verification, not only from mathematics, but also because human beings can't ever know about all those things. Even if you told me that 5,000 scientists believed all those things to be true. I am not one of the 5,000 scientists who will ever do that. I will ultimately always have to rely on faith and confidence in these other people to tell me that these things are true. And those scientists have to rely on something about each other. We simply can't get inside other people's heads.

21stC: Are you positing that the faith in other people, to acquire the knowledge and perform the work they do, is also connected to the faith in these unknowables that have always been the province of religion and some forms of philosophy?

Moore: In the history of science, people have always struggled with the problem of credibility. Some people have been discarded as nut cases, as quacks; occasionally, and happily not all that often, as frauds. But I think that there is a process in scientific research where you have to have faith in somebody's methods, judgment, and wisdom.

Park: That's why we come down so hard on frauds: because we have to trust each other. A lot of people ask me, of these cloning experiments, "Has this been verified?" As a matter of fact, my answer is yes. People have looked at it, but what they're looking at was provided by Wilmut.

Moore: There are people who don't believe anyone landed on the Moon; I don't quite understand that, but I understand the logic of it: they didn't see it and they weren't there. But this radical separation of notions of belief from the endeavor of trying to understand things in science is not a useful distinction. Now, not a whole lot of people engage in scientific research; you have to be very sure about who these people are. We have screening mechanisms called colleges and universities that weed out the people who do crazy things or can't be trusted. If everybody was able to produce knowledge, this would be frightening, if we thought everything everybody said was equally valuable. But we trust people, and then we can sometimes verify the stuff so that it's good enough to make the things we need.

Horgan: I'm trying to make a functional distinction between science and religion. Science is after truth, regardless of the consequence, whereas religion isn't at all about truth; religion doesn't give a damn about truth. I can only make sense of religious faith in terms of making people feel like there's something in charge that knows what's going on, that we're here for some reason.

Park: If one looks over the history of religion, not all religions have had that purpose at all. They have been ways of controlling people, by and large.

Albert: Not only that, but there's a long theological tradition of arguing, attempting to prove propositions about God. So to say it's not about truth strikes me as wrong. There are methodological differences between the way theological and scientific debates proceed, including the role of empirical observation.

Horgan: But they "know the truth" in advance. That's the difference. What's the difference between a creationist and an evolutionary biologist?

Park: The difference is just enormous.

Horgan: Exactly. One is after truth, and one already knows what the truth is.

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DAVID ALBERT, PhD, is professor of philosophy at Columbia and holds a doctorate in theoretical physics from Rockefeller University.

JOHN HORGAN is a senior writer for Scientific American and the author of The End of Science: Facing the Limits of Science in the Twilight of the Scientific Age (Addison-Wesley, 1996).

KELLY MOORE, PhD, is assistant professor of sociology at Barnard and is currently working on a study of scientists' participation in political protest.

ROBERT PARK, PhD, is professor of physics at the University of Maryland and director of public information for the American Physical Society.

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