Stephen Jay Gould on Prediction

Summary Review of a talk given at McGill University on November 4, 1998.


The Harvard University paleontologist and evolutionary biologist spoke eloquently to a packed house in Leacock 132 last Wednesday on "Why we can't predict the future: A Millennial Perspective."

Gould noted that there is a long tradition of scientists who liked to claim that they could tell the future, given enough information. While science has largely put aside such claims, many people mistakenly view that as a failing.

"We understand that scientific fields do not lend themselves to predictability, and we see them as the worse for it. We see the inability to predict as our limit. When we fail to accurately predict, that is not our limitation, that is just nature's reality. The reason we can't make predictions is the enormous complexity of nature, and the randomness thrown in, when you try to explain a unique and particular series of events."

Gould said that the desire to predict stems from the human need to find meaning in chance events.

"We have to extract meaning out of the confusion of the world around us. We do it by telling stories, and by looking for patterns. And whenever we see a pattern, we have to tell a story about it" This leads us to think that we can predict, when so much of the 'patterning' we see is really just a clumping of results within a random system."

Numerous studies have debunked beliefs in patterns. Gould gave the example of a study examining every field goal shot by the Philadelphia 76ers NBA team for an entire season, to see if any patterns emerged.

"Every basketball fan, including myself, knows perfectly well that there is an important phenomenon known as 'hot hands.' Every once in a while, the shots just start to click for a player; he sinks them one after the other. Well, the study found that, statistically, there is no such thing as hot hands."

Players were only getting statistically probable "hot streaks."

"They found that the number of sequences of, say, six baskets in a row that players get are the number that they should get, statistically, based on their field goal percentage. Naturally, players with higher percentages have longer and more frequent sequences. Yet, no matter how many times you explain this study, people just won't buy it, because 'everybody knows' that hot hands is a part of the game."

As a corollary to the urge to prognosticate, people tend to look at world history and prehistory and claim that certain events -- like the emergence of human beings -- were inevitable and predictable.

"We deny the contingent nature of history. We spin doctor the results of evolution to say that they were inevitable, from stooped apes to white men in business suits" First there were dinosaurs, and now there are mammals, and why should that be so? There are laws of nature that questions like that entail, but fundamentally, it's a narration. It's an unpredictable narration that can only be explained after it happens."

Gould scoffed at the notion that humanity was inevitable; he says that our knowledge of prehistory demonstrates that it was more of an accident of evolution.

"When you look at mass extinctions, some of which were quite catastrophic, those events can be removing some groups and letting others through. We are not here because mammals slowly made their superior way against dinosaurs for hundreds of millions of years" mammals existed as small creatures which could not make any headway in a world ruled by dinosaurs. We eventually emerged on top only because dinosaurs were wiped out."

Gould quoted Darwin's opinion that the survival of any species, including homo sapiens, is a mere detail in nature's big picture. And he debunked the notion that the existence of our species points to a higher meaning in the universe.

"There is a popular philosophical argument which states: if the laws of the universe were just a tad different, we couldn't be here. And the fact that we are here must mean that some 'higher power' wants us to be. It just doesn't follow. Yes, if the laws were a tad different, some other creatures would be here instead of us. And it would be just as good a universe, and just as explainable according to those laws, except that there would be pulsating sheets of electrons instead of self-conscious creatures."

Gould concluded by stating that the view expressed in his lecture -- in which destiny and inevitability is replaced by nearly infinite possibility -- is a salutary one.

"This view that I've been presenting strikes many people as depressing and negative. I think that's the wrong way to look at it. The massive and unpredictable contingency in nature gives us control, freedom and consequential responsibility. I find this view of life exhilarating; we are the offspring of history, of contingency. We must establish our own path in a universe quite indifferent to our suffering, but offering us maximal freedom to thrive, or fail, in our chosen way."

Gould's talk was sponsored by the Redpath Museum and the Department of Biology. Gould was recently named an Honorary Doctor of Science by McGill.