Popper puzzled over the stark contrast between the non-scientific character of Freud and Adler 's theories in the field of psychology and the revolution set off by Einstein 's theory of relativity in physics in the early 20th century. Popper thought that Einstein's theory, as a theory properly grounded in scientific thought and method, was highly "risky", in the sense that it was possible to deduce consequences from it which were, in the light of the then-dominant Newtonian physics , highly improbable (., that light is deflected towards solid bodies—confirmed by Eddington's experiments in 1919 ), and which would, if they turned out to be false, falsify the whole theory. In contrast, nothing could, even in principle, falsify psychoanalytic theories. He thus came to the conclusion that psychoanalytic theories had more in common with primitive myths than with genuine science. 
In the Enlightenment there was a revival of interest in logic as the basis of rational enquiry, and a number of texts, most successfully the Port-Royal Logic , polished Aristotelian term logic for pedagogy. During this period, while the logic certainly was based on that of Aristotle, Aristotle's writings themselves were less often the basis of study. There was a tendency in this period to regard the logical systems of the day to be complete, which in turn no doubt stifled innovation in this area. However Francis Bacon published his Novum Organum ("The New Organon ") as a scathing attack in 1620 .  Immanuel Kant thought that there was nothing else to invent after the work of Aristotle, and the famous logic historian Karl von Prantl claimed that any logician who said anything new about logic was "confused, stupid or perverse." These examples illustrate the force of influence which Aristotle's works on logic had. Indeed, he had already become known by the Scholastics (medieval Christian scholars) as "The Philosopher", due to the influence he had upon medieval theology and philosophy. His influence continued into the Early Modern period and Organon was the basis of school philosophy even in the beginning of 18th century.  Since the logical innovations of the 19th century, particularly the formulation of modern predicate logic , Aristotelian logic had for a time fallen out of favor among many analytic philosophers .