The discovery of black swans in Western Australia in 1697 ruined the Roman idiom, “As impossible as a black swan.” Just one black swan falsifies the statement, “All swans are white.”

I was taken to task by commentators responding to last week’s rant (Monsanto, GMOs and Vitamin A Deficiency) for, among my many sins, my claim that science doesn’t deal in certainties. I don’t just claim it, I state and proclaim it. Science is provisional. Nothing is certain, but, of all the ways we have of thinking about our world, science is at least explicit about our uncertainty. We don’t know, and we’ll never know for sure.

But (big but) it’s the best we’ve got. Science is the best way we have to counter our prejudices, intuition, genetic make-up that make us all hopelessly biased from the get-go. For instance:

  • We’re born into a tribe—family, ethnicity, religion, race, neighborhood, friends—which give us a skewed view of the world: my six-year old world isn’t your six-year old world.
  • We go to school where we’re taught according to the dominant beliefs of our country or state, by teachers with their own biases.
  • We’re stuck with genes that tell us to divide the world into our people (with whom we cooperate) and those people (the competition).
  • We’re bombarded with news from biased, if-it-bleeds-it-leads, sources; news is business. (Shark attacks are headline news, despite the fact that they account on average for one human death per year.) (While humans kill 100 million sharks annually.)
  • La gente es mala. In the absence of information, we’re more likely to think the worst of people than the best. (Which could explain the results from a January 2015 Pew poll that asked two groups if GM foods are generally safe: 37% of the general public said yes, compared to 88% of AAAS scientists.)

Here’s a terrific TED talk about our prejudices.

Science is a process (not a set of beliefs) that helps lift us out of our innate biases while giving us a progressively more accurate understanding of the world and ourselves. How do we know whether a theory is scientific or not? As I say, there’s never 100% certainty, but here are a few yardsticks; the more a theory meets these criteria, the more likely it is to be truer than what came before. A good scientific theory is:

Explanatory. Intelligent design (sic) claims that a universe as complicated as ours needs a designer…which explains nothing, since presumably a designer has to be smarter than the acts it performs. ID simply subsititutes one gap in knowledge with another. (What created the designer?) Science tries to go beyond such circular thinking.

Consistent. Gravity (for instance) works the same here as it does everywhere in the universe, and always has done. That’s the assumption that makes cosmology possible.

Parsimonious. This is the “less is more” principle. Occam’s Razor is frequently cited, to the effect that the fewer assumptions a theory makes, the better. When Newton proposed that an apple falling from a tree followed the same simple law as the moon orbiting around the Earth, he was being parsimonious. (* The attractive force between two bodies is proportional to the product of their masses and the inverse of the square of their distance apart.)

Falsifiable. You can never make enough observations to be certain a theory is true, but the statement, “All swans are white” is disproved by finding just one black swan.

Predictive. You can test a theory by using it to predict the result of future experiments.

Correctible. A theory can be modified if future observations don’t follow predictions. (Newton/Einstein.)

Provisional. The latest theory is true until it isn’t. (I’ve interviewed many scientists over the past 30 years, and one trait I notice is their skepticism; any new idea is immediately questioned by critics who want to disprove it.)

This all sounds good in theory, of course. In practice, science is done by scientists with their own agenda for fame and fortune, tenure, power, sex and all the rest of it. But science’s built-in capacity for self-correction gives it a leg-up over the competition.

As I say, it’s the best we’ve got.


Barry Evans gave the best years of his life to civil engineering, and what thanks did he get? In his dotage, he travels, kayaks, meditates and writes for the Journal and the Humboldt Historian. He sucks at 8 Ball. Buy his Field Notes anthologies at any local bookstore. Please.