I've been making my way through Johnjoe McFadden's book Life is Simple:How Occam's Razor Set Science Free and Shapes the Universe. It traces the history of science through the lens of Occam's razor.
William of Occam, who was born in the late 13th century, is famous for favoring the simplest solutions in theology, science, and other areas of life.
The book says, "Three centuries after his death, the French theologian Libert Froidmont coined the term "Occam's razor" to refer to William's preference for shaving away excess complexity."
But contrary to how many people look upon Occam's razor, this doesn't mean that reality is simple. McFadden says:
Kepler's next step was, albeit reluctantly, to add more complexity. This is of course perfectly compatible with Occam's razor, which, contrary to many of its detractors, does not insist that the world is simple, only that in reasoning about it we should not multiply entities beyond necessity.
If the existing entities cannot do the job then the razor gives you free rein to add as many entities as needed, so long as they are not 'beyond necessity'.
...'Entities' refers to the parts of an hypothesis, explanation or model of any particular system.
Models come in for a lot of attention in the book.
The most familiar example is the numerous epicycles in the Ptolemaic model of the solar system, which assumed Earth sits at the center of it. In order to match observations of the sun and planets, smaller circles had to keep being added on to the large circles that was wrongly assumed to be how the planets moved.
(Now we know it is an ellipse, and the sun is the center of the universe.)
What's interesting is that very different models can each be a reasonable-sounding explanation for some aspect of reality. Thus a good model is one that can be used to steadily improve our knowledge of reality, something that religious models, theologies, are utterly incapable of doing.
Our scientific model remains, not in the world, as Aristotle insisted, or in some mystical realm, as Plato proposed, but, according to Occam, in our head. The ultimate reality of what is really out there in the world will always be beyond our reach, as unknowable as Occam's omnipotent God.
...Models instantiate knowledge. They model the structure, dynamics and function of machines [among other things], usually in the language of geometry and mathematics. They can be as simple as the drawing of a steam engine, such as Newcomen's in 1712 that refers to Boyle's 'weight of air' to account for the motion of the piston.
The feature that makes them so useful is that improvements can be fed back into the model as a positive feedback loop that leads to exponential increases in performance. Yet models are useless without Occam's razor.
Imagine trying to build a steam engine if your model of how it works was based on More's 'knowing spirit'. How would you improve it? Perhaps you might pray to its spirit?
When this approach failed, your only recourse would have been the geologically slow process of trial and error that has been responsible for most innovations on our planet, including life itself, since the dawn of time.
This all changed when scientists and engineers shifted to using models that instantiated their knowledge and their scientific laws and, as Boyle had urged, were 'the Simplest it must be: at least from all that is superfluous, free'.
With razored models in hand, scientists and engineers could predict modifications that would improve performance. If their prediction was realised, then the engineer knew their model was good; if not, the engineer would modify their model until their predictions held true and they obtained the desired improvement.
Their improved model would then be a starting point for further advances. With this positive feedback loop in place, technological development went from the linear rate of improvement delivered by trial and error to the exponential advances that characterise the modern age.
Well, religious and mystical beliefs don't even improve at a linear rate. They never improve at all, at least not in regard to explaining the nature of reality.
One big reason for this is that dogmatism and blind faith prevail in religions.
So a religion isn't even capable of proving itself wrong -- with logically must be the case for nearly every religion given that religions contradict each other (or indeed every religion) -- because theological models don't include a capacity to test how well they match up against reality, with feedback providing a way to improve the theology.
Such as by discarding it as totally false.
Instead, the same old dogmas are preached year after year, decade after decade, century after century. This is why science constantly progresses and religions remain the same insofar as their capacity to explain reality.