Is Anything Certain in Science?

This article was originally posted on RealClearScience.

Last week, I was at a coffee shop working when a lady approached me and invited me to attend a science discussion group. The topic was the “limits of science.” Intrigued, I put away my laptop and joined the group, which consisted mainly of elderly people who were thoughtful, well-spoken, and seemingly intelligent. I had no idea what to expect in terms of the tone of the conversation, so I listened eagerly as the discussion leader (who has a master’s degree in geology) started the meeting.

“Science is subjective, though we like to think of it as objective,” he began. “When I speak of ‘facts,’ I put them in quotation marks.” He elaborated that things we once thought to be true were later overturned by further study.

Right away, I knew I was going to be in for a ride. While the geologist didn’t clarify exactly what he meant, we can deduce one of two things: Either (1) he does not believe facts are real or (2) he believes facts are not accessible to scientific investigation.

Both of these beliefs are problematic from a scientific viewpoint. The first implies that there is no such a thing as a fact, and hence, no such thing as truth. My favorite philosophy professor, former mentor, and (I’m honored to say) friend, Robert Hahn of Southern Illinois University, once quipped, “If the ultimate truth about the universe is that there is no truth, what sort of truth is that?” I would add that if there is no such thing as truth, then science is merely chasing after the wind. Science would be pointless. As fictitious Tottenham Hotspur coach Ted Lasso would say, “Why do you even do this?”

The second belief poses a much bigger challenge to science because there is no convincing response to it. Philosopher Immanuel Kant wrote of the noumenon (actual reality) and thephenomenon (our experience of reality). Because we experience reality through our imperfect senses, we do not have direct access to it. For instance, we perceive plants as green, but that is simply the result of our eyes and brains processing photons and interpreting them as the color green. How do we know that perception is reliable? Isn’t it possible that plants are actually some other color? Given that we are limited by our sensory capabilities, we can never know the answer to that question. Our experience of the greenness of a plant (phenomenon) is separate from the underlying reality of a plant’s color (noumenon).

Humans in general, and scientists specifically, ignore this philosophical challenge. We assume that our perception of reality matches actual reality. Do we have any other option? How could we live daily life or accept the findings of scientific research if we believed otherwise?

The point of that lengthy aside is that the geologist’s comment was at odds with a practical scientific worldview. But, things got even weirder after that.

When our conversation turned to the reliability of the scientific method, I commented, “Scientific laws are generalized in such a way that if you perform an experiment like a chemical reaction on Earth or on Mars, you should get the same result.”

One of the ladies asked, “But how do we know? We’ve never been to Mars.”

I answered, “We have a basic understanding of how chemical reactions work. To our knowledge, they aren’t affected by gravity.* So, we should get the same reaction on Mars.”

“In theory.”

Well, yes, in theory. But this sort of extreme skepticism is difficult to address. Chemistry is a mature science whose basic principles are well understood. Until we have sufficient reason to believe otherwise, we should expect chemical reactions to be identical whether they are performed on Earth or on Mars.

Strangely, a bit later on, the same skeptical lady asked me, “How do you explain telepathy?” She added that there have been times when, as she was speaking to another person, that she knew what the other person was going to say before she said it.

“Scientists don’t believe telepathy is real. That’s how I explain telepathy,” I responded.

“Some scientists do believe in it,” retorted the geologist.

True. But, some scientists believe that HIV doesn’t cause AIDS. That doesn’t mean we should take them seriously. I decided to elaborate: “Think of all the times that you thought of words, but nobody said them. Or all the times you thought of somebody, but they didn’t call. You forget all of those, but you remember the few times where a coincidence occurred. That’s called confirmation bias.”

Unsurprisingly, I didn’t win her over. The conversation then took one final turn.

The skeptical lady believed the future would be run entirely by robots and machines. This is referred to as the “singularity” and has been popularized by Ray Kurzweil. It is also probably bunk. Not only are we unable to model a worm’s brain accurately, but the scientific knowledge and sheer computing power necessary to properly replicate a human brain — with its 86 billion neurons and some 100 trillion synapses — are massive. Besides, there is no compelling reason to believe that computing power will grow exponentially forever. Eventually, some mundane physical factor will limit our technological progress. If (and that’s a big if) the “singularity” is even possible, it is likely centuries away.

Our evening ended there. Over the next 24 hours, I pondered what could make otherwise intelligent people embrace pseudoscience and science fiction? Moreover, what could make a person doubtful of chemistry, but accepting of telepathy?

I’m still not sure, but I have a clue. Conspiracy theorists are known to believe contradictory ideas. For instance, as Live Science reported, “people who believed [Osama] bin Laden was already dead before the raid were more likely to believe he is still alive.” Similarly, the lady who believed that science wasn’t advanced enough to fully understand chemistry yet also somehow so advanced that it could build Earth-conquering robots may be engaging in conspiracy-like thinking. She had no awareness that her skepticism of chemistry and credulity toward telepathy were, in many ways, fundamentally incompatible.

Extreme skepticism and extreme credulity are anathema to the scientific mindset. Successful scientists accept the reliability of the scientific method but question extraordinary claims that are not founded upon extraordinary evidence. That is healthy skepticism, and it was curiously absent from the science discussion group.

*Note: The kinetics of chemical reactions could possibly vary under different gravitational conditions. See an interesting discussion here.