Uniformitarianism and Occam's Razor

 Sir James Hutton

Uniformitarianism is the principle (expounded by James Hutton, Charles Lyell and others) that present-day rocks and landscapes can be interpreted by reference to presently observable processes, and that these processes have always been in operation through space and time.  In its earliest form, the Principle of Uniformitarianism denied a role for catastrophic (high intensity and intermittent, unpredictable or erratic) events, as a reaction against the Biblical mythology of Noah's Flood, but earth scientists have long since recognized that catastrophic events (even extraterrestrial ones) DO happen, and that they are observable either on the surface of today's planet Earth or in the geological record -- so catastrophism does nothing to destroy the validity of the Principle.
   
    As far as the science of landscape is concerned, our principle is this:  If a past phenomenon can be understood as the result of a process now acting in time and space, do not invent or invoke an extinct or unknown or supernatural  cause as its explanation.  By the same token, if a landscape can be understood by reference to known physical processes, even if they have varied through space and time because of climate change or crustal movements, do not bring in "invented" processes which are unverifiable through observation.

Stephen Gould (1987):  “We should try to explain the past by causes now in operation without inventing extra, fancy, or unknown causes, however plausible in logic, if available processes suffice.”

This is known as the scientific principle of parsimony or Occam's Razor.  This is a good definition: "Of two equivalent theories or explanations, all other things being equal, the simpler one is to be preferred".  

"Strict uniformitarianism may often be a guarantee against pseudo-scientific phantasies and loose conjectures, but it makes one easily forget that the principle of uniformity is not a law, not a rule established after comparison of facts, but a methodological principle, preceding the observation of facts . . . It is the logical principle of parsimony of causes and of economy of scientific notions. By explaining past changes by analogy with present phenomena, a limit is set to conjecture, for there is only one way in which two things are equal, but there are an infinity of ways in which they could be supposed different." (Hooykaas 1963)

One doesn't want to get too involved in the philosophy of all this, apart from saying that in my past life as a scientist I sought always to look initially for the simplest possible natural explanations for phenomena, with working hypotheses formulated and later often falsified and modified.  (I was greatly influenced too by Popper's ideas on the role of falsification in science.)

It's because of all this that I am steadfastly unimpressed by the theories (aired by Kostas and Robert on this blog) which seek to "explain" Stonehenge by reference to sloping Neolithic sheets of ice or Mesolithic landscape inundations by water.  Not only are these theories unsupported by observations on the ground and by reference to equivalent processes operating today, but they are also entirely unnecessary and overly complicated.  According to Occam's Razor, the theories are not actually needed -- and for that reason they are best disregarded.  Of course, one understands why the theories have been put forward -- there is an insatiable desire out there in the big wide world for NEW THINGS to be written about the "mystery of Stonehenge".  I suppose I am guilty of that crime myself!!

On the principle that the simplest possible explanations of Stonehenge are the ones to go for, until they have to be replaced, I also feel strongly that Herbert Thomas and Richard Atkinson behaved in a fashion that was scientifically indefensible, and even reprehensible, by failing to give due consideration to the simplest and most logical explanation of how the bluestones got to Stonehenge -- as glacial erratics, as suggested by Judd, Jehu and others in the late 1800's and early 1900's.  They wanted fame and notoriety, so they both dumped or disregarded the Principle of Uniformitarianism and went for a wacky and unsupportable theory of human transport that had no empirical evidence to back it up it a century ago, and still has none today.

We do not NEED floods of Biblical proportions, or conveniently sloping Neolithic sheets of ice, or gangs of Neolithic hauliers, to get bluestones moved from the west of Wales to the chalk downs of Wiltshire -- the downland landscape, and the presence of bluestones on or near Salisbury Plain, can be explained quite simply and logically by reference to natural processes which are well observed and well documented.