The ‘settled science’ and its leaning tower

I was reading a piece by the American commentator Adam Gopnik, “A point of view: science, magic and madness”, in which he described Galileo testing the theory that bodies of dissimilar weight plunge to the ground at the same rate by dropping cannon balls of different sizes off the Tower of Pisa.

It is not hard centuries later to find people who still assume that heavier bodies fall faster. I know; I have met them. I put it down to lack of attention in science classes in school and, after all, to be fair, common observation tells us that feathers fall more slowly than, say, a tennis ball. Balloons fall slowly and sometimes rise. It is at this point that scientists are needed to explain what is meant by the theory.

Little, it turns out, is simple. Apparently, only in a vacuum do bodies of all shapes and sizes fall at the same rate. Let me say at this point that my scientific knowledge is very limited. Would a larger cannon ball of the same weight as a smaller one fall absolutely at the same rate through air? I suspect it would, but I don’t know for sure whether additional surface area makes a difference.

What I think I do know is that two cannon balls of the same size and shape but of different weights would fall at the same rate through air. Hold on, supposing one cannon ball had only a thin sliver of metal covering and was filled with hydrogen or helium? Some might object that this would not be a cannon ball at all but a stage prop. The conversation might become tangential about what is and what isn’t a cannon ball.

At this point common sense needs to be applied. Someone who paid attention in science class needs to say, okay, air pressure and wind make a difference but the essential point is that two similar shaped and sized bodies weighing, say, 10 kilograms and 100 kilograms fall at exactly the same rate when dropped from the same point at the same time. For the non-scientific community that suffices in homing in on a fundamental piece of what might be called, to choose a loose term, “settled science”.

Why is it “settled” for the non-scientific community? It is settled because Galileo and scientists like him have assumed that it is not settled and have conducted many experiments any one of which could have falsified the theory. Not one did. It therefore remains determinedly unfalsified and should be relied upon. I say should be relied upon because progress and parts of daily life would become unmanageable if we constantly questioned everything anew. Our comfort is that scientists are forever foraging away – Wikipedia-like – to make a name for themselves by correcting today’s “truths”. They take nothing as settled.

Einstein’s special theory of relativity, unlike quantum mechanics, makes sense to me as a layman. It seems unarguable, as one explanation I read put it, that a light beam travelling from the ceiling of a moving train takes longer to reach the floor from the point of view of an observer on the platform than for someone on the train; and correspondingly that the train traveller on his return will have aged less than the observer. No more need be said; end of story. Hold on, that’s not at all scientific.

Science accepts nothing at face value. Planes were sent speeding around the globe replete with atomic clocks to check the theory. It was not falsified. If it had been, then however convincing was the theory it would have been proved wrong. As Gopnik so well puts it: the approach of modern science “is simply the perpetual assertion of experience over authority, and of debate over dogma”.

A friend of mine accepts the truth of serious man-made global warming because he maintains that the majority of climate scientists believe it to be so. Leaving aside the validly or otherwise of his premise; his is a layman’s appeal to authority, which is reasonable enough it seems to me.

The overwhelming majority of us have no way of determining whether CO2 emissions will cause runaway global warming. We must, perforce, rely upon the scientific community. But, and it’s a big but, we are entitled as laymen to understand that scientists are forever foraging away trying to disprove the global warming theory.

It would be unsettling if scientists started describing the global warming theory as “settled” or of giving that impression to impressionable commentators. That is a layman’s term properly reserved for describing things like the coincident landing of two cannon balls of different weight dropped from the same height at the same place at the same time.

What I want to know is that climate scientists are, figuratively speaking, scaling the heights of the Tower of Pisa cannon balls in hand. Nothing that I read or hear gives me confidence that this is happening with any conviction. Is this simply a communications problem? Has every country got a Tim Flannery front-man inadvertently queering the pitch and putting science in a bad light? Or, is there really something rotten in the state of climate science?

Peter Smith, a frequent Quadrant Online contributor, is the author of Bad Economics