This principle is definitely known to some here - others maybe not, just adding this to the discussion in relation to trying to unravel events:
Occam's razor (or Ockham's razor[1]), is the meta-theoretical principle that "entities must not be multiplied beyond necessity" ( entia non sunt multiplicanda praeter necessitatem) and the conclusion thereof, that the simplest solution is usually the correct one.
The principle is attributed to 14th-century English logician, theologian and Franciscan friar, William of Ockham. Occam's razor may be alternatively phrased as pluralitas non est ponenda sine necessitate ("plurality should not be posited without necessity")[2]. The principle is often expressed in Latin as the lex parsimoniae (translating to the law of parsimony, law of economy or law of succinctness). When competing hypotheses are equal in other respects, the principle recommends selection of the hypothesis that introduces the fewest assumptions and postulates the fewest entities while still sufficiently answering the question. It is in this sense that Occam's razor is usually understood. To quote Isaac Newton, "We are to admit no more causes of natural things than such as are both true and sufficient to explain their appearances. Therefore, to the same natural effects we must, so far as possible, assign the same causes."[3]
In science, Occam’s razor is used as a heuristic (rule of thumb) to guide scientists in the development of theoretical models rather than as an arbiter between published models.[4][5] In the scientific method, Occam's razor is not considered an irrefutable principle of logic, and certainly not a scientific result.[6][7][8][9]
[edit] Controversial aspects of the Razor
Occam's razor is not an embargo against the positing of any kind of entity, or a recommendation of the simplest theory come what may[33] (note that simplest theory is something like "only I exist" or "nothing exists").
The other things in question are the evidential support for the theory.[34] Therefore, according to the principle, a simpler but less correct theory should not be preferred over a more complex but more correct one.
It is this fact which gives the lie to the common misinterpretation of Occam's Razor that "the simplest" one is usually the correct one.
For instance, classical physics is simpler than more recent theories; nonetheless it should not be preferred over them, because it is demonstrably wrong in certain respects.
Occam's razor is used to adjudicate between theories that have already passed 'theoretical scrutiny' tests, and which are equally well-supported by the evidence.[35] Furthermore, it may be used to prioritize empirical testing between two equally plausible but unequally testable hypotheses; thereby minimizing costs and wastes while increasing chances of falsification of the simpler-to-test hypothesis.
Another contentious aspect of the Razor is that a theory can become more complex in terms of its structure (or syntax), while its ontology (or semantics) becomes simpler, or vice versa.[36] The theory of relativity is often given as an example of the proliferation of complex words to describe a simple concept.
Variations
The principle is most often expressed as Entia non sunt multiplicanda praeter necessitatem, or "Entities should not be multiplied beyond necessity", but this sentence was written by later authors and is not found in Ockham's surviving writings. This also applies to non est ponenda pluritas sine necessitate, which translates literally into English as "pluralities ought not be posited without necessity". It has inspired numerous expressions including "parsimony of postulates", the "principle of simplicity", the "KISS principle" (Keep It Simple, Stupid).
Other common restatements are: Entities are not to be multiplied without necessity.
and The simplest answer is usually the correct answer.
A restatement of Occam's razor, in more formal terms, is provided by information theory in the form of minimum message length (MML). Tests of Occam's razor on decision tree models which initially appeared critical have been shown to actually work fine when re-visited using MML. Other criticisms of Occam's razor and MML (e.g., a binary cut-point segmentation problem) have again been rectified when—crucially—an inefficient coding scheme is made more efficient.
"When deciding between two models which make equivalent predictions, choose the simpler one," makes the point that a simpler model that doesn't make equivalent predictions is not among the models that this criterion applies to in the first place.[32]
Leonardo da Vinci (1452–1519) lived after Ockham's time and has a variant of Occam's razor. His variant short-circuits the need for sophistication by equating it to simplicity. Simplicity is the ultimate sophistication.
Another related quote is attributed to Albert Einstein Make everything as simple as possible, but not simpler.
Occam's razor is now usually stated as follows: Of two equivalent theories or explanations, all other things being equal, the simpler one is to be preferred.
As this is ambiguous, Isaac Newton's version may be better: We are to admit no more causes of natural things than such as are both true and sufficient to explain their appearances.
In the spirit of Occam's razor itself, the rule is sometimes stated as: The simplest explanation is usually the best.
Another common statement of it is: The simplest explanation that covers all the facts is usually the best.