Ockham's Razor.

I Find Karma (adam@cs.caltech.edu)
Wed, 11 Feb 1998 00:00:02 -0800

A friend asked me what Ockham's Razor is, so I looked it up.


> William of Ockham, a Franciscan, was born around 1290 in Surrey, and
> died in Munich. He studied at Oxford University and wrote extensively
> on the theological and philosophical issues of the time. By the
> principle later known as 'Ockham's Razor,' he insisted that ' what can
> be done with fewer.... is done in vain with more'; the mind should not
> multiply things without necessity, an extension of 'Franciscan'.
> Denounced as a heretic to Pope John XXII, he was summoned to Avignon
> in 1324 where he got into further hot water and entirely rejected the
> secular authority of the papacy. William fled to the service of the
> Emperor Louis of Bavaria in 1328, almost certainly dying of the plague
> that ravaged Europe in 1349.


> What is Ockham's Razor?
> Ockham's Razor is the principle proposed by William of Ockham in the
> fifteenth century: ``Pluralitas non est ponenda sine neccesitate'',
> which translates as ``entities should not be multiplied
> unnecessarily''.
> The reason behind the razor is that for any given set of facts there
> are an infinite number of theories that could explain them. For
> instance, one can explain the motion of the planets by Newton's theory
> or by the theory that each celestial body has a computer-controlled
> motor which makes it move the way it does; the computer code was
> generated by an advanced alien race which chose the motions of the
> planets because they look nice. The first theory has one explanation
> for the data, the second requires a new explanation (a different kind
> of motor and a different computer code) for each new celestial body we
> see.
> The above example is too obvious. It sometimes happens that the simple
> theory is very difficult to discover. It took a long time for us to
> realize that the Earth is not the center of the universe.
> The Razor doesn't tell us whether a hypothesis is true or false, it
> rather tells us which one to test first. The simpler the hypothesis,
> the easier it is to shoot down.
> A related rule, which can be used to slice open conspiracy theories,
> is Hanlon's Razor: ``Never attribute to malice that which can be
> adequately explained by stupidity''.


> If scientific theories keep changing, where is the Truth?
> In 1666 Isaac Newton proposed his theory of gravitation. This was one
> of the greatest intellectual feats of all time. The theory explained
> all the observed facts, and made predictions that were later tested
> and found to be correct within the accuracy of the instruments being
> used. As far as anyone could see, Newton's theory was ``the Truth''.
> During the nineteenth century, more accurate instruments were used to
> test Newton's theory, and found some slight discrepancies. Albert
> Einstein proposed his theories of Relativity, which explained the
> newly observed facts and made more predictions. Those predictions have
> now been tested and found to be correct within the accuracy of the
> instruments being used. As far as anyone can see, Einstein's theory is
> ``the Truth''.
> So how can the Truth change? Well the answer is that it hasn't. The
> Universe is still the same as it ever was. When a theory is said to be
> ``true'' it means that it agrees with all known experimental
> evidence. But even the best of theories have, time and again, been
> shown to be incomplete: though they might explain a lot of phenomena
> using a few basic principles, and even predict many new and exciting
> results, eventually new experiments (or more precise ones) show a
> discrepancy between the workings of nature and the predictions of the
> theory. In the strict sense this means that the theory was not
> ``true'' after all; but the fact remains that it is a very good
> approximation to the truth, at lest where a certain type of phenomena
> is concerned.
> When an accepted theory cannot explain some new data (which has been
> confirmed), the researchers working in that field strive to construct
> a new theory. This task gets increasingly more difficult as our
> knowledge increases for the new theory should not only explain the new
> data, but also all the old one: a new theory has, as its first duty,
> to devour and assimilate its predecessors.
> One other note about truth: science does not make moral
> judgments. Anyone who tries to draw moral lessons from the laws of
> nature is on very dangerous ground. Evolution in particular seems to
> suffer from this. At one time or another it seems to have been used to
> justify Nazism, Communism, and every other -ism in between. These
> justifications are all completely bogus. Similarly, anyone who says
> ``evolution theory is evil because it is used to support Communism''
> (or any other -ism) has also strayed from the path of Logic (and will
> not live live long nor prosper).

Example of nonscience nontruth -- perpetual motion machine



Tell me all your thoughts on God, 'cause I'd really like to meet Her,
and ask Her why we're who we are.
-- Dishwalla