Peshkin replies: We scientists need to teach the nonscientist public what science is about: what an established theory is and how we know when it’s right; how the requirement of falsifiability serves as a fence between science and nonscience, defining the limitations of science and insulating it from attacks based on pseudoscience; and especially why science, correctly understood, does not threaten most people’s religious beliefs.
Michael Matthews says that the approach I advocate is condescending to the religious. It has not been so perceived by the several dozen people who have approached me after my public lectures or in response to my writings for the public. A majority of the many who identified themselves as people of religious faith, from high-school students to the former president of a theological seminary, started the conversation by saying that they appreciated my respect for religion. Nevertheless, Matthews’s warning should be heeded. People can be hypersensitive to unintended slights about their religion, especially slights from scientists. If you do not have respect for people’s religion, you should not be conducting such discussions; if you do have that respect, you should make it obvious from the outset. You don’t have to pretend to share your audience’s religious beliefs; you only have to respect them. Otherwise, people will tune you out.
Matthews misrepresents the fence I described. It surrounds—and is defined by the demands of—science, not religion. Nobody can reasonably deny religion its own perspectives regarding natural phenomena as well as religious beliefs. Science’s fence is violated only if a pretense is made that such a discussion is science when it is not. That point of violation is the reason for the conflict, and that is where we have to guard against attempts to substitute pseudoscience for science in our schools. Explaining the conflict to the public has not been made easier by recent contemptuous attacks on religion by atheists who are scientists but who abuse science when they claim falsely that it disproves religion. I explicitly disown such attacks and advise others to do the same.
Matthews, joined by David Morrison and Moorad Alexanian, also objects to my use of experiment as the sole criterion for defining science; they say observation is also part of science. They are right. Henceforth I will say “experiment and observation,” but that alone does not address the substance of their complaint. The subtleties of the difference between experiment and observation and their interaction with predictive power and falsifiability may be suitable for advanced students, but they cannot usefully be addressed in a typical one-hour general-interest lecture, at least not by me. Each person who gives such talks has to use an approach with which he or she is comfortable. I am comfortable with describing the discovery of the cosmic microwave background as a make-or-break experiment that could have falsified the Big Bang theory. Big Bang cosmology was on a back burner until the CMB was predicted and subsequently discovered. Was that an experiment or an observation? I don’t think it matters. An example from geology is the speculation that the K-T extinction was caused by a meteor impact. That idea became generally accepted when its prediction of a global iridium-rich layer at the right depth was confirmed experimentally—or was it observationally? Absent that widespread iridium, the theory would have been falsified. That’s what made it science.
Testing the theory is more difficult in biology. Biologists can tout simple individual experiments and observations that test evolution, but biologists are also dependent on the overall success of the big picture, the observation of which must agree with their theories. I defer to the biologists for an authoritative description of all that. My point is that what is science and what is not remains the same.
Morrison also suggests that we drop the word “theory” because it has diverse meanings. Particle physicists and astrophysicists often do just that, speaking instead of “the standard model.” I see no useful answer to the argument that evolution is “just a theory” other than to explain what an established scientific theory is and why it must be respected despite our near certainty that future research will find its applicability limited.
Alexanian says that experiments to test evolution’s description of the origin of the earliest life forms are not possible. We can never prove that any theory is true; we can only challenge it with tests. The famous Miller–Urey experiment and its successors, in which amino acids were created from hydrogen, methane, carbon dioxide, and water in a process that credibly mimics nature, constitute such a test.
Joe Heafner serves his students well by discussing the nature of evidence and related questions. I hear anecdotally that others are beginning to do the same. I hope they will all emphasize the limitations of science and why science and religion, reasonably understood, do not threaten each other.
Juan Roederer addresses issues that go beyond the conflict we currently face in our schools and our courts. He seeks a generalization of science and religion into a philosophy that not only includes both but creates a unified system in which the two are non-trivially entangled and which satisfies the core needs of both. The clarity with which Roederer describes that ambitious quest in a short letter is remarkable. However, its success is uncertain, as is the time scale on which we will learn whether it succeeds. Protecting the teaching of good science in our public schools cannot wait. We must defend the science we have, which is distinct from religion, and we must do it now.
I note that Roederer enjoins science to “turn away from the easy way out offered by the anthropic principle.” But observations of atomic spectra in distant quasars hint at a slight shift in the fine structure constant. If that result is confirmed, the improbability of finding conditions right for life somewhere at some time becomes at least a semi-quantitative question that needs to be investigated by the methods of science.
Keith Schofield makes three substantive points: that his experience as a chemical physicist leads him to believe that DNA cannot have arisen in a natural process, that physicists should butt out and leave the discussion to biologists, and that scientists have a faith of their own. The first is asserted without explanation and the second seems curious in light of the first. Schofield’s third point is interesting. I think most scientists take on faith that there is some understandable pattern to the things we can observe, that we are on the right track in investigating that pattern by the methods of science, and that we are closing in on something that corresponds to our intuitive idea of reality. That belief is a matter of our meta-science, or perhaps of our psychology, not part of the science itself, which deals only with the observable world. The important thing for the present discussion is that this belief neither confirms nor contradicts religion.
Michael Todhunter asks to debate the evidence for evolution in the fossil record. Books have been written on that subject—I cited two in my Opinion piece. The practical political issue is this: What should our public schools teach when confronted with disagreements they are not themselves able to resolve? The answer is easy. Almost all the most respected biologists are saying that evolution is the theory that works and that it is the central organizing principle of modern biology. If the school boards have any sense, that is what their schools will teach despite a few dissenters, some of whom offer genuine scientific challenges to the theory and most of whom have other agendas. The schools should be teaching their students that all theories have wrinkles that remain to be ironed out. They should be teaching that all theories are tentative and our understanding is always incomplete, but that science progresses by building on what we know best. Well-established theories such as evolution work too well not to have mostly permanent truth in them, even though the theories will evolve in response to new evidence. We should be helping the school boards by educating their constituents.
Contrary to Schofield’s advice, all kinds of scientists should be explaining to the public what science is about and emphasizing its strengths and its limitations, because the public and not the courts will decide where this country will go in the 21st century.