Draft Foreword

"Give me a fruitful error any time, bursting with the seeds of its own corrections. You can keep your sterile truth to yourself." (Wilfredo Pareto)

The basic foundation axiom of the historical sciences – the thing that makes them sciences, rather than history, or philosophy – is uniformitarianism. This is the principle that the same physical laws should apply everywhere, and everywhen. We do experiments with corn starch and clay here on the surface of the Earth, and expect the same rheological correlations we find to apply deep in the interior of distant planets. We do experiments with the nucleic acids of fruit flies, and expect them to shed light on the reproduction of the primordial protoplasmic globule that was the ancestor of all life. We measure the spectra of ions in flames at a thousand degrees, and use them to infer the composition of stars.  We drop balls from towers and deduce laws that allow us to calculate the movement of galaxies.

Why do we accept uniformitarianism? What makes us think the universe is constructed in such a way that every part of it obeys the same laws? That our corner of it is not some freakish backwater dancing to its own drum?  Ultimately, we accept uniformitarianism because it is more fruitful than the alternatives. If the same laws apply here on Earth as in the heavens, we can in principle understand the motions of celestial bodies. If the same laws apply now as applied millions of years, we can in principle understand how life began. It is a purely pragmatic assumption, because it allows to knuckle down and get to work doing something.

And it works. We have pushed this principle back through billions of years and out to the limits of the observable universe, and everywhere we go uniformitarianism seems to work.  Of course, that does not mean that we won’t find something out there tomorrow.  There is no fundamental reason why the universe should necessarily obey the same laws everywhere. There is no reason why these laws should be simple enough that creatures that have evolved within the universe can hope to understand them. Yet, gloriously enough, both those things seem to be true. We haven’t observed any strange astronomical phenomena, or found anything buried under kilometres of limestone, that on careful examination we haven’t been able to explain by the laws we’ve worked out to explain what is happening here, now.

Now, as well as being enormously fruitful in terms of explaining the universe, this purely pragmatic assumption we have made has one other startling property.

It is the simplest assumption we could make.  

This has nothing to do with its effectiveness. But, it means that tangled up with all of our historical sciences – with astronomy, geology, biology – we have the idea, explicitly or implicitly, that the simplest explanation is always best.  In the absence of any other reason to select one explanation over another, we go with the simplest one, as a principle of how we do science.

“Entia non sunt multiplicanda praeter necessitatem” – William of Ockham never said this...

“Everything should be made as simple as possible. But not simpler” – Albert Einstein never said this...

But they did say similar things:

“Frustra fit per plura quod potest fieri per pauciora” (It is futile to do with more things that which can be done with fewer) – William of Ockham

“It can scarcely be denied that the supreme goal of all theory is to make the irreducible basic elements as simple and as few as possible without having to surrender the adequate representation of a single datum of experience” – Albert Einstein

These quotes express the principle of parsimony. This principle is a powerful tool for driving progress. I think it is justified on pragmatic grounds, because it is easier to test and use a simple model than a complicated one. I think it is, and should be, the default way of tackling a mass of competing hypotheses.

But...

I also think that a reading of history tells us that the simple model never turns out to be the right one. The parsimonious explanation on incomplete data always turns out to be a gross oversimplification of the explanation that takes all the data into account, or to be entirely incommensurate with that better explanation. Parsimony is a road that leads somewhere, that lets us stretch our legs, but doesn’t in the end take use where we want to go.

It is worth repeating: it is just a coincidence that uniformitarianism is the assumption suggested by parsimony, as well as the one that seems to work.

This happy coincidence, Marco Parigi believes, has infected our thinking, retarding the progress of science.  We need uniformitarianism, and we see its pragmatic success is a vindication of parsimony.  So we think we need parsimony, too. Marco thinks that we have set parsimony up as a false God, and sacrifice perfectly good alternative theories at its altars. Theories that, as more information comes in, will prove to be superior to the ones that we have garlanded with flowers, the darlings of parsimony.  And he is correct.

David Sangster, a senior colleague of mine who worked in the British nuclear program just after the Second World War, was fond of saying: ‘Just because the explanation fits the data, it doesn’t mean the explanation is true.’ This is something every working scientist has engraved on their heart. Parsimony is a tool to select a working hypothesis that can be tested further – a good servant, but a terrible master.

Marco believes he has identified an alternative method of selecting the best working hypothesis from a mass of postulated alternatives – a method he calls ‘Marcomony’. He has tried to explain it to me numerous times, but it has never made any sense to me. This work is his latest attempt. And whether it succeeds or not, it is an attempt that is well worth making. Progress does not come from taking small steps in the direction everyone else is going. It comes from making wild leaps in directions nobody in their right mind would go. Nothing frustrates me more than arguing with people who have crazy ideas simply because everyone else around them has the same crazy ideas;  but arguing with someone who has their own crazy ideas: that is one of my favourite things.

So, I would like to wish Marco the best of luck with this endeavour. Maybe I will understand Marcomony when it is finished: maybe I won’t. Either way, his ringing denunciation of parsimony and visceral hunger for an alternative has an important message for all scientists. (Which is just another way of saying, everyone.)

IMHO.

“I must create a system, or be enslaved to another man’s” – William Blake

A/Prof Christopher Fellows