Thursday

Newton introduced his concept of the “method of analysis and synthesis” in the queries of the Opticks. He intended this as a defense of his methods in the Opticks and the Principia, and not as a statement of his actual research method. The concept became associated among Newtonians in Britain and the Netherlands with a search for causes, and in particular with force and the Principia, and not with the experimental discovery of “ingredients” in optics—light rays of different color— and chemistry—elements or principles. In a parallel tradition, both before and after Newton, chemists continued to use the term “analysis” for the decomposition of a compound body. Although Newton used the method of analysis and synthesis in some demonstrations of his theory of light and color, it did not play a prominent role in demonstrating his theory because of some inherent problems. Nor did he use the terms “analysis” and “synthesis” in the text of the Opticks other than in the queries.

Galen of Pergamum (129–216 CE), the influential Greek medical writer and philosopher, offers detailed discussion of various kinds of mixture (krasis) in organic and inorganic substances. ‘Mixture’ is a central concept in his theory of the human body; at the same time, ‘mixture’ also figures prominently in his account of the powers of medical substances such as foods, drinks and drugs, whose efficacy, he argues, is to be described in terms of specific kinds of interaction between the body’s mixture and that of the medical substance administered (and the mode of administration). While he insists that the natural mixture of the body displays a degree of interpenetration of ingredients which is not attainable for artificially created mixtures, he also believes that the latter can interact with the former in a way that leads to therapeutic success. Moreover, he argues that the (human) body’s perfect mixture, and especially that of the human hand, provides the doctor with a subtle sense of tactile discrimination enabling highly accurate assessment of the patient’s mixture and allowing correspondingly fine-tuned therapeutic intervention.

Galen further offers detailed remarks about the testing of medical substances. These are subsumed under his concept of ‘qualified experience’, which includes a number of requirements that have to be met in order for drug trials to have evidential value, and which in some respects anticipates later theories of scientific experimentation.        

Analysis and synthesis have always stood at the heart of the science of chemistry.  The archaic German word for chemistry itself, Scheidekunst, points toward the immemorial centrality of analysis; the preparation of novel materials, beginning perhaps with Egyptian blue in the Old Kingdom, suggests the similar pervasiveness of synthesis.  But synthesis and analysis developed in unique new directions during the course of the nineteenth century.  This presentation will explore the significance of these activities for the testing of theories, functions that by this time had become both distinctive and highly effective for the science of chemistry.

Early modern academic physicians followed Galen’s models on many points, including reasoning from signs of diseases back to hidden causes and from causes to signs. Galen’s Art of Medicine (Tegni) famously spurred reflections on the methods of teaching and discovery, which included his categories of analysis, synthesis, and dissolution of the definition. Medieval and early modern physicians at times described analysis as reasoning from effects to causes, and synthesis from causes to effects. Their actual practices departed from Galen’s terms and models in important ways, such as their frequent omission of patients’ idiosyncratic qualitative temperaments, but diagnosis often depended on moving backward from signs to causes, and back. At patients’ bedsides, physicians also moved forward in time, observing disease progression and the effects of therapeutic interventions. From the early 1600s on, physicians at Leiden University followed the Paduan model and used post-mortem dissections to confirm or go beyond the diagnoses and prognoses made during daily clinical teaching in the local hospital. Galenic physicians did not develop radically new medical theories, but they did gradually add to the store of pathological and therapeutic knowledge based on their knowledge of diseases and therapies going forward with living patients, and their inferences from post-mortem evidence back to the historical causes of patients’ diseases and deaths. By the mid-1600s, this established pedagogical practice allowed physicians and students pushing new medical theories to generate important new pathological knowledge, notably of consumption (phthisis).

In this paper, we aim to elucidate two chemical experiments referenced by Kant in the preface to the second edition of the Critique of Pure Reason. The first — what Kant calls “the experiment of reduction” — we argue is actually the Reductio in Pristinum Statum, popularized a century earlier by Wittenberg chymist Daniel Sennert. The second is Georg Ernst Stahl’s famed phlogiston experiment, in which charcoal is added to lead calx in order to regenerate the metal. Both experiments investigate unobservable matter — corpuscles and phlogiston, respectively — by manipulating a substance through chemical analysis. That analysis is followed by a synthesis with some external component, which results in a reduction to the substance’s original state. We then show how Kant consciously uses these experiments as a model for his own synthetic method to accomplish his aim of securing metaphysics as a science. On this basis, we provide a new interpretation of Kant’s synthetic method. We argue that it consists in a three-stage process: 1) a hypothesis about unobservable entities; 2) an analysis of a whole into its elements; and, 3) a synthesis of those elements back into a whole. Kant uses such a method to confirm his revolutionary thought that metaphysics is based on “the altered method of our way of thinking, namely that we can cognize of things a priori only what we ourselves have put into them”.