Occam's Razor = The Law of Parsimony (-1899)

"We may assume the superiority ceteris paribus [other things being equal] of the demonstration which derives from fewer postulates or hypotheses." (Aristotle, “Posterior Analytics”, cca. 400 BC)

 

"Always take the short cut; and that is the rational one. Therefore say and do everything according to soundest reason." (Marcus Aurelius, "Meditations". cca. 121–180 AD)

"We consider it a good principle to explain the phenomena by the simplest hypothesis possible." (Ptolemy)

"That is better and more valuable which requires fewer, other circumstances being equal. [...] For if one thing were demonstrated from many and another thing from fewer equally known premises, clearly that is better which is from fewer because it makes us know quickly, just as a universal demonstration is better than particular because it produces knowledge from fewer premises. Similarly in natural science, in moral science, and in metaphysics the best is that which needs no premises and the better that which needs the fewer, other circumstances being equal." (Robert Grosseteste,” Commentarius in Posteriorum Analyticorum Libros”, cca. 1217–1220)

"It is superfluous to suppose that what can be accounted for by a few principles has been produced by many." (Thomas Aquinas, “Summa Theologica”, cca. 1266-1273)

"All that is superfluous displeases God and nature. All that displeases God and nature is evil." (Dante Alighieri, "De Monarchia", cca. 1312-1313)

“Numquam ponenda est pluralitas sine necessitate.”
“Plurality is never to be posited without necessity.” (William of Occam, “Quaestiones et decisiones in quattuor libros Sententiarum Petri Lombardi”, 1495)

"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, as far as possible, assign the same causes." (Isaac Newton, "Philosophiæ Naturalis Principia Mathematica" ["Mathematical Principles of Natural Philosophy"], 1687) 

"Entia non sunt multiplicanda praeter necessitatem."
"Entities are not to be multiplied beyond what is necessary." (John Ponce, cca. 17th century)

"It is, after all, a principle of logic not to multiply entities unnecessarily." (Antoine-Laurent Lavoisier, "Réflexions sur le phlogistique", 1862)

"The first obligation of Simplicity is that of using the simplest means to secure the fullest effect." (George H Lewes, "The Principles of Success in Literature", 1865)

"The question is therefore to demonstrate all geometrical truths with the smallest possible number of assumptions." (Augustus de Morgan, "On the Study and Difficulties of Mathematics", 1898)

"In scientific thought we adopt the simplest theory which will explain all the facts under consideration and enable us to predict facts of the same kind. The  catch in this criterion lies in the world 'simplest'." (John B S Haldane, "Possible Worlds and Other Essays", 1928) 

"For if as scientists we seek simplicity, then obviously we try the simplest surviving theory first, and retreat from it only when it proves false. Not this course, but any other, requires explanation. If you want to go somewhere quickly, and several alternate routes are equally likely to be open, no one asks why you take the shortest. The simplest theory is to be chosen not because it is the most likely to be true but because it is scientifically the most rewarding among equally likely alternatives. We aim at simplicity and hope for truth." (Nelson Goodman, "Problems and Projects", 1972)

"Scientists must use the simplest means of arriving at their results and exclude everything not perceived by the senses." (Ernst Mach)