Sunday, 19 June 2011

Strange change - 1500 to 1700

E A Burtt was an American philosopher who among a number of other books, wrote The Metaphysical Foundations of Modern Physical Science, first published in 1924. I came across Burtt’s book in a second-hand bookshop while on holiday and couldn’t put it down. Although it doesn’t reach any startling conclusions, there is something curiously compelling about it.

Burtt is concerned with fundamental changes to the European world-view during the two centuries from about 1500 to 1700. He begins with Copernicus and Galileo who as we all know, changed our Ptolemaic, Earth-centred cosmology to a heliocentric cosmology.

Burtt begins his story by pointing out that neither Copernicus nor Galileo had much in the way of empirical evidence for such a radical change. Copernicus knew that a few ancient Greeks though a heliocentric cosmology would be simpler, so he set out to prove it. Even so, the resulting Copernican cosmology was merely simpler than Ptolemaic, in that the celestial geometry was simpler with far fewer epicycles. Galileo thought that the simpler cosmology of Copernicus was reason enough to adopt it, even without observational support.

So the Catholic Church may have treated Galileo badly, but it was not denying any powerful observational facts because there weren’t any. Empirical support for Copernicus came along later of course, but for many decades Ptolemaic cosmology still explained all observations within accuracies attainable at that time. Even Galileo’s discovery that Jupiter has moons could probably be explained under the old theory by adding a few more complexities.

However, this is cosmological change just the beginning of a profound change to our whole world-view. Burtt’s main interest is further scientific developments brought about by Sir Isaac Newton and his universe of bodies moving under the action of gravity, interacting through known mathematical laws. A cosmos governed by cause and effect rather than medieval ideas of logic and teleological causes. Oddly enough though, when Burtt examined Newton’s writings, he found nothing to suggest what this famous and extremely influential scientist found so compelling about this new science of bodies moving under the influence of forces governed by mathematical laws of cause and effect.

Burtt’s conclusion is that maybe science could have gone in any one of a number of other directions, initiating possibilities now lost to us largely because of Newton’s success and the way his authority continued long after his death. Even Einstein made no fundamental change to a world-view based on mathematical laws operating through cause and effect.

Possibly the world of external facts is much more fertile and plastic than we have ventured to suppose; it may be that all these cosmologies and many more analyses and classifications are genuine ways of arranging what nature offers to our understanding, and that the main condition determining our selection between them is something in us rather than something in the external world.
Edwin A Burtt – The Metaphysical Foundations of Modern Physical Science

I sometimes speculate on the possibilities we may have missed if Burtt was right, so what follows are my thoughts, not Burtt’s. He was more circumspect.

Consider a scenario where medieval logic rather than mathematical laws of cause and effect is the basis of empirical science. This would be a logic different to the symbolic logic of modern logicians. Its axioms would often be empirical data, linking logic to the real world in a way we now find more difficult than it ought to be. In this world for example, economics would be just as scientific as physics. I suspect it is anyway, but that's another issue.

So consider the statement, do as you would have others do. This moral law might be derived from the logic of social cohesion. It would be just as ‘scientific’ as e=mc2 and just as ‘true’. Divisions between science and non-science could be less significant than they are in our Newtonian world. Arguments would be more logically-based, more easily resolved by clarifying the axioms, or simply by agreeing that different axioms lead to different conclusions. We can do this now of course, but maybe it isn’t as easy as it could have been.

Obviously we can’t push ideas like this too far, because we are where we are, but perhaps Burtt was right and things could have been different. Suppose, in this imaginary non-Newtonian world, we were considering the issue of climate change. Anyone could argue logically as follows:-

Climate change theory suggests the climate is unstable with respect to CO2.
Atmospheric CO2 has been much higher in the past than it is now.
During those times, the climate was not unstable.
Therefore the climate is not unstable with respect to CO2.

This argument is over-simplified of course, because it is intended to make a point about an entirely imaginary non-Newtonian world, but in this world, the argument would be powerful, probably conclusive and easily understood by non-specialists.


Mark Wadsworth said...

Surely everything is a mixture of observation and logic?

For example, the Chinese discovered acupuncture as a spin-off from spending centuries sticking needles into people to see what happened, and it seems to work, even though it's only modern scientists who can explain why.

Conversely, homoeopathy is based entirely on some allegedly logical assumptions, and it either works or doesn't work, depending on how open or closed minded you are.

As to Galileo, he did a lot of observing and he made up his mind that Aristarchus was right about heliocentricity. They've now sent space craft to the edge of the solar system, and the theory stacks up, although it is possible that it is wrong.

Either way, we know that in a century's time, they will look back and laugh at some of the nonsense we believe today.

A K Haart said...

Logic isn't supposed to tell us anything about the real world though, even though we know it does. A logically true statement would be a tautology (so the argument goes) and empty of real-world meaning.

'Blue things are always blue', for example, doesn't tell you anything.

Burtt's thesis is quite complex and subtle and all I'm really trying to do in this post is point people towards his book should they be sufficiently interested.