Philipp Frank on Jacob Bronowski

“[V]on Mises and Hilda Geiringer raised the objection that in Reichenbach's theory a theory was said to be "valid with a probability of 70%," if 70 per cent of the conclusions of the theory were confirmed by experiment. However, we know... a theory which is in disagreement with experience in 30% of... experiments is called "false" or "wrong." We come to the same conclusion if we apply Carnap's "inductive probability." An attempt to avoid these difficulties and to advance a radically different approach... was made by Jacob Bronowski. His purpose was to formalize the criterion for the validity of a theory that was advocated by men like John Frederick Herschel and William Whewell. ...these scientists and philosophers saw the main achievement of a theory in its unifying and simplifying power. The simpler the theory... the more probable the theory. If the theory consists in a complete enumeration of all observable facts, the "theory" would have a very high probability... However, von Mises and Bronowski rejected this... If we have two theories which yield the same observable facts, the scientist prefers the... more economical or just simpler. Bronowski compares the scientific theory with a code... We prefer the code which is more practical, more efficient. ...to improve the code, we try systematically... "to break down the code into its constituent symbols and their laws of arrangement." ...If we break down [chemical] elements into... elementary particles (protons, neutrons, and electrons) and the forces acting between them, we have a code which describes... the interaction between hydrogen and oxygen... from which can be derived much more information than from any theory in which "oxygen" and "hydrogen"...occur as primitive symbols. ...Bronowski calls a theory the more probable, the more the code... is broken down into constituent symbols and laws of arrangement.”

“Every acceptance of a debatable theory is due to a compromise between Reichenbach's and Bronowski's criteria: agreement with facts and efficiency as a code.”

“The criteria of Reichenbach and Carnap, which are based, like John Stuart Mill's inductive logic, upon agreement with observations, have to be complemented by the criterion of economy and simplicity which was advanced in the history of science by men like William Ockham, Isaac Newton, and Ernst Mach. In out twentieth century, the importance of criteria other than mere agreement with observation was stressed by von Mises and Bronowski.”