Defending Science: An Exchange

ByMICHAEL P. LYNCHandALAN SOKAL

http://opinionator.blogs.nytimes.com/2012/03/11/defending-science-an-exchange/

Last fall, after Michael Lynchs essay Reasons for Reason appeared in The Stone, he began correspondence with the physicist, mathematician and writer Alan Sokal about the nature and limits of scientific rationality. The following exchange is adapted from that original dialogue.

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MICHAEL LYNCH: Heres something that often gets lost in the acrimony of the culture wars: the public debate over evolution isnt just about evolution. It is also about which sources or methods we should trust science or scripture when it comes to the history of life on this planet.

As I noted in an earlier post for The Stone, Reasons for Reasons, this can be described as a debate over first principles. Not moral principles, but epistemic first principles. Epistemic principles tell us what is rational to believe and what sources and methods for forming beliefs are worthy of our trust.

Debates over epistemic principles sound abstract, but they have enormous practical repercussions. For instance, in order to decide policy matters (like what to put in our textbooks and what to teach in science classrooms) we need to decide on the facts. But in order to decide on the facts, we need to decide on the best ways for knowing about those facts. And to do that, we need to agree on our epistemic principles. If we cant, stalemate ensues. Each side looks at the other as if they inhabit a completely different world and in a sense, they do.

So it is perplexing, even worrying, that debates over really fundamental epistemic principles can seem irresolvable. The problem is that you cant defend first principles without presupposing them that is what makes them first principles. As a result, when debates reach this point, they can seem rationally irresolvable. We cant defend our principles without arguing in a circle.

The problem of justifying first epistemic principles is very old. It led the ancient Greek skeptics to say that knowledge is an illusion. But over the centuries, it has been more common to draw a different conclusion, one concerning the relative value of reason itself. According to many people, what the problem of justifying first principles really shows is that because reasons always run out or end up just going in circles, our starting point must always be something more like faith.

There is a grain of truth in this disquieting thought. We cant reasonably defend our trust in science just by doing more science in the hope of persuading those who arent already on board. But that doesnt mean we cant give reasons for our first principles, including the epistemic principles of science. Of course we can. The hard question is what sort of reasons we can give.

ALAN SOKAL: I think you are absolutely right that the core disagreements between, to use your example, fundamentalist Christians and the rest of us are ultimately over epistemic principles. But I would argue that the epistemic challenge from fundamentalist Christians (and more generally from religious people of all kinds) can be fairly easily answered where here of course I mean giving a logically efficacious answer, not necessarily a psychologically or politically efficacious one.

The point is, simply, that fundamentalist Christians epistemic principles are not, at bottom, so different from ours. They accept as evidence the same types of sense experience that the rest of us do; and in most circumstances they are attentive, just like the rest of us, to potential errors in the interpretation of sense experience.

The trouble is not that fundamentalist Christians reject our core epistemic principles; on the contrary, they accept them. The trouble is that they supplement the ordinary epistemic principles that we all adopt in everyday life the ones that we would use, for instance, when serving on jury duty with additional principles like This particular book always tells the infallible truth.

But then we have a right to inquire about the compatibility of this special epistemic principle with the other, general, epistemic principles that they and we share. Why this particular book? Especially, why this particular book in view of the overwhelming evidence collected by scholars (employing the general epistemic principles that we all share) that it was written many decades after the events it purports to describe, by people who not only were not eyewitnesses but who also lived in a different country and spoke a different language, who recorded stories that had been told and retold many times orally, and so on. Indeed, how can one possibly consider this particular book to be infallible, given the many internal contradictions within it?

By contrast, the results of modern science can be justified, I think, by using the general epistemic principles that we all share. The reasoning is long, and nonexperts may not be able to follow it in all details but nonexperts should be able to understand the general outlines of the argument (and the fact that most citizens dont is a major scandal concerning the teaching of science).

Of course, I dont think that, as a psychological matter, most fundamentalist Christians are likely to give up their belief anytime soon as a result of such arguments. (But some will: for instance, the renowned New Testament scholar Bart Ehrman recounts in some of his recent books how he started out adulthood as a passionate fundamentalist Christian, anxious to read the infallible word of God in its original Greek and only when he did, and started studying its internal contradictions and the history of its composition, he realized that fundamentalist Christianity was untenable.)

But I do think that this approach is logically sound: not as a way of justifying our epistemic principlesab initio[from the beginning] or justifying them to a hypothetical person whose epistemic principles are nearly opposite; but as a way of justifying them to all human beings who actually exist.

MICHAEL LYNCH: There are some things we have in common including some principles just because we are human. As the Scottish philosopher David Hume pointed out, you can doubt induction or observation all day long, but youll still end up trusting them later that night. As he put it, it is just part of our natural instincts to trust our senses most of the time. That is how we are built.

As you point out, Professor Sokal, maybe we can justify some of our scientific practices simply by appealing to what we have in common. This is a very important point, and any attempt to defend the first principles of science must begin there. But it cant end there, for two reasons.

First, the fact that most folks believe some principle doesnt make it true, as Hume would have been the first to point out. The relevant epistemic principles are fundamental precisely because any attempt to justify them is circular. (Think of trying to give a logical argument for trusting logic, or basic inference patterns likemodus ponens).[1]That problem doesnt go away just because most people will accept certain principles.

The second reason we cant rest content with the fact that some principles are widely shared is that some debates are over thepriorityof principles. Some people reject the idea that scientific reasoning should always trump more traditional methods of knowledge. Thus, believers in creationism typically dont deny induction and abduction (coming up with the best explanation of the data) full stop. Rather they deny that these principles have priority everywhere. Imagine, for example, a dispute over these two principles:

(A) Abduction from the fossil and physical record is theonlymethod for knowing about the distant past.

(H) Consultation of the holy book is thebestmethod for knowing about the distant past.

The friends of (H) arent rejecting abduction outright: they are merely asserting that in some situations abduction is trumped by the more fundamental principle (H). So we cant just call them out for using abduction in some cases and not in others. And obviously, we cant travel back in time and use observation (another commonly shared method) to settle who is right and who isnt about the distant past. What that shows is that debates over even very specific principles like these can end up grounding out either the participants will end up defending their favored principles by appealing to those very principles (citing the book to defend the book) or appealing to other specific principles that the other side shares but gives a lower priority. So shared natural instincts and methods cant always win the day, simply because the problem isnt always about what is in common. The problem is about what trumps what.

Now, I am not saying that there is nothing we can say about the relative merits of (A) over (H). Of course there is lots to say. My point is that it illustrates that conflicts over some epistemic principles arent going to be settled by appealing to still more epistemicprinciples.

ALAN SOKAL: Yes, its hard to imagine what anab initio justification of logical principles likemodus ponenswould look like. But I guess that I have never gotten much worked up over this problem: all of us who are interested in discussing more serious problems (be they in philosophy, science, mathematics, politics or anything else) have no choice but to usemodus ponens(and a lot of other things).

Likewise for sense experience and for knowing what information, if any, it gives about the external world (though this is a much more serious issue in my opinion thanmodus ponens): solipsism and radical skepticism[2]are irrefutable, as far as I can see, but that does not mean there is any reason to take them seriously. In practice no human being does even philosophers stop being solipsists or radical skeptics when they are shopping for dinner.

Induction is, of course, very difficult to justify (in part because its degree of justification varies case by case). But I like the way Jim Brown formulated the naturalist argument [in "Who Rules in Science? pp. 119-120]:

Certain reasoning patterns tend to promote survival; others dont. If Og reasoned: In the past tigers have regularly eaten people, but Im sure this one will be quite friendly, then very likely Og is not your ancestor.

This is why our fundamental epistemic principles, such as observation and induction, are well-nigh universal among human beings.

But it is your second point concerning the comparison of epistemic principles which I perhaps dont understand. If creationists deny that abduction from the fossil record is the best method to learn about the distant past, what method do they recommend as superior? Reading the Bible? It seems to me that the relative value ofthesetwo methods can be readily understood by using our ordinary general epistemic principles and fundamentalist Christians would approve perfectly the structure of the reasoning, if we were dealing with a nonreligious document (for instance, Thomas Jeffersons detailed account of events that allegedly took place in Philadelphia in 19,000 B.C.) or the sacred writings of another religion (like the Bhagavad-Gita). The problem, it seems to me, is not that we really have any disagreement in our fundamental epistemic principles; it is simply that fundamentalist Christians have special epistemic principles that in factconflictwith their general principles (once one takes into account certain relevant observational data), but they dont see that fact (perhaps they are not aware of all the relevant data) and perhaps they dont wantto see it even when the relevant data are brought to their attention.

I should stress that there can be serious debates of this type. For instance, the Jesuit astronomers who doubted the reliability of Galileos telescopic observations were not being completely irrational: the telescope was a new invention; little was yet understood about how it worked and how reliable it was for observing distant objects (the theory of optics had not yet been much developed).Of course, over time these objections were (mostly) removed by careful study of telescopes and optics. (I say mostly because, even after optics had been well developed, physicists did not yet know about gravitational lensing.)

MICHAEL LYNCH: You point out that certain forms of reasoning are likely to promote survival. Og and his buddies had a greater chance of sticking around and making little Ogs if they relied on induction and observation to get by in the world. No quarrel there. But that is just my point: defending scientific principles of rationality by appeal to their survival value is to cite practical, not epistemic, reasons in their defense. Of course, survival value is hardly the only sort of practical reason we can cite on their behalf. We can endorse their usefulness in helping us build bridges and cure diseases. And we can although this is a longer story also defend them as having a more democratic character. What Ive been arguing we cant do is defend epistemic first principles with more epistemic principles.

Id like to end on a point of agreement. One of the deepest threats to rationality is from those who use skeptical arguments as dialectical tools for what I call leveling-down purposes. There is a long history of this in Western philosophy and theology, and not just with advocates of religion. Postmodernists use these arguments too (as Professor Sokal knows well). The basic thought is: The methods [of science say, or whatever] cant be shown to be reliable in a noncircular fashion [insert skeptical argument]. Therefore the methods of science are no more rational than any other. They are all on a level.

From this, the traditional ancient skeptic concluded: believe nothing, because no belief is produced by a reliable method. The evangelical concludes: only nondiscursive faith or revelation can get us the truth. The postmodernist concludes: no method can get us to the truth because there is no (objective) truth.

I think we agree that all these answers, especially the latter two, are terrible, philosophically and politically. We might even agree that we cant answer the skeptical argument on its own terms there is no epistemic magic bullet. What we disagree about is what more we can say. As I said inan earlier post, I think we can justify our first epistemic principles our trust in science but I think that will involve appealing to something more than the epistemic principles themselves. It will involve showing that a commitment to the epistemic first principles of science is an important, perhaps even an essential, feature of any democratic society.

FOOTNOTES

[1] An example ofmodus ponens: From the premise thatifSpot is a dog, then he is warmblooded, and the additional premise that Spot really is a dog, we can infer that Spot is in fact warm-blooded. This is such a basic pattern of deductive inference that it is hard to see how we could justify it without relying on it at some point.

[2] Radical skeptics say we dont know anything about the external world because we cant rule out all possible sources of mistake, e.g., the possibility that we have been massively deceived by a malevolent God. (See,skepticismentry at The Stanford Encyclopedia of Philosophy).

Michael P. Lynch is a professor of philosophy at the University of Connecticut. His new book is In Praise of Reason.

Alan Sokal is professor of physics at New York University and professor of mathematics at University College London.

He is a co-author with Jean Bricmont of Fashionable Nonsense: Postmodern Intellectuals Abuse of Science (Picador USA, 1998) and the author of Beyond the Hoax: Science, Philosophy and Culture (Oxford University Press, 2008).

This post has been revised to reflect the following correction:

Correction: March 12, 2012

A previous version of this article included an erroneous sentence in the quote from the book "Who Rules in Science?" by James Robert Brown. It has been corrected.