Don’t always believe what scientists and other authorities tell you! Be skeptical! Think critically! That’s what I tell students, and some learn the lesson all too well.
I want to give students the benefit of my hard-won knowledge of science’s fallibility. Early in my career, like most science writers, I celebrated scientists’ achievements, from theories of cosmic creation, and the origin of life to the latest treatments for depression and cancer.
Eventually I realized that journalists like me were presenting the public with an overly optimistic picture of science. By relentlessly touting alleged advances and by overlooking all the areas in which scientists were spinning their wheels, we made science seem more potent than it really is.
Now, I urge students to doubt the claims of physicists that they are on the verge of explaining the origin and structure of the cosmos. String and multiverse theories, I point out, cannot be confirmed by any conceivable experiment. This isn’t physics, it’s science fiction with equations!
I give the same treatment to theories of consciousness, which attempt to explain how a three-pound lump of tissue — the brain — generates perceptions, thoughts, memories, emotions, and self-awareness. Some enthusiasts assert that scientists will soon reverse-engineer the brain so thoroughly that they will be able to build artificial brains much more powerful than our own
Balderdash!, I tell my classes (or words to that effect). Scientists have proposed countless theories about how the brain absorbs, stores, and processes information, but researchers really have no idea how the brain works. And artificial-intelligence advocates have been promising for decades that robots will soon be as smart as HAL or R2-D2. Why should we believe them now?
Maybe, just maybe, I suggest, fields such as particle physics, cosmology, and neuroscience are bumping up against insurmountable limits. The big discoveries that can be made have been made. Who says science has to solve every problem?
So how do my students respond? Some react with healthy push back, especially to my suggestion that the era of really big scientific discoveries might be over. “On a scale from toddler knowledge to ultimate enlightenment, man’s understanding of the universe could be anywhere,” wrote a student named Matt. “How can a person say with certainty that everything is known or close to being known if it is incomparable to anything?”
Other students embrace skepticism to a degree that dismays me. Cecelia, a biomedical-engineering major, wrote: “I am skeptical of the methods used to collect data on climate change, the analysis of this data, and the predictions made based on this data.” Pondering the lesson that correlation does not equal causation, Steve questioned the foundations of scientific reasoning. “How do we know there is a cause for anything,” he asked.
In a similar vein, some students echoed the claim of radical postmodernists that we can never really know anything for certain, and hence that almost all our current theories will probably be overturned. Just as Aristotle’s physics gave way to Newton’s, which in turn yielded to Einstein’s, so our current theories of physics will surely be replaced by radically different ones.
After one especially doubt-riddled crop of papers, I responded, “Whoa!” (or words to that effect). Science, I lectured sternly, has established many facts about reality beyond a reasonable doubt, embodied by quantum mechanics, general relativity, the theory of evolution, and genetic code. This knowledge has yielded applications — from vaccines to computer chips — that have transformed our world in countless ways.
It is precisely because science is such a powerful mode of knowledge, I said that you must treat new pronouncements skeptically, carefully distinguishing the genuine from the spurious. But you shouldn’t be so skeptical that you deny the possibility of achieving any knowledge at all.
My students listened politely, but I could see the doubt in their eyes. We professors have a duty to teach our students to be skeptical. But we also have to accept that, if we do our jobs well, their skepticism may turn on us.
John Horgan directs the Center for Science Writings, which belongs to the College of Arts & Letters. This essay is adapted from one originally published in The Chronicle of Higher Education.
