Bayesian reasoning is a method based on inferences. This reasoning builds from observations a probability of the cause of a given event. The adjective “Bayesian” comes from British mathematician Thomas Bayes (1702-1761). It is him who formulated Bayes’ theorem which designates the conditional probability of A knowing B.
Scientific positivism is a doctrine developed by Auguste Comte (1798-1857) in the Cours de philosophie positive, published from 1830 to 1842. It is based on three pillars, which are the best known contributions of Comtian thought: the law of three states, the classification of sciences and sociology, not without political influence. Wishing to fight against metaphysics which he considers abstract and vague and against theology which is based on beliefs which are in fact unverifiable as such, he initiates what is called positive philosophy. Scientific positivism establishes that the human mind, in perpetual quest to know things that it is not able to reach, must renounce the absolute because it is unable to grasp the essence itself of the things that pique his interest. This implies that the knowledge that derives from the human mind cannot overcome the barriers of scientific laws. Positive philosophy must therefore tackle the study of scientific laws without going beyond them, which would amount to doing what experimental science does when it discovers new laws.
Conventionalism is a doctrine stipulating a fundamental separation between the data of intuition and the senses and the intellectual constructions making it possible to found scientific or mathematical theories.
This notion was first created by Henri Poincaré (1854-1912), then developed by Pierre Duhem and Édouard Le Roy, in quite different forms, at the border of the 19th and 20th centuries (although none of these authors did not use the term “conventionalism”). It finds its deep origin in the Kantian separation between intuition and concept.
Verificationism, also called verificationist theory of meaning, is an epistemological conception used in the philosophy of language and shared by the logical positivism of the Vienna Circle. It affirms that a statement can only have cognitive meaning, that is to say is likely to be true or false, if it can be verified by experience. It is also called logical empiricism in that the results of the experiment are supposed to confirm the supposed validity of a theory, or else refute it. The other statements are either analytical, and “meaningless” (sinnlos), or synthetic but not verifiable by experience, and therefore “absurd” (unsinnig). This distinction between sinnlos and unsinnig comes from Wittgenstein’s Tractatus logico-philosophicus, which influenced the program of the Vienna Circle.
(Includes texts from Wikipedia translated and adapted by Nicolae Sfetcu)