Descartes’ Method

Statue of Descartes in Amsterdam

In my blog last week, I criticized Descartes’ idea to build knowledge on an indubitable foundation. For Descartes this foundation was a condition for knowledge acquisition. How did Descartes come to knowledge, given this indubitable foundation, so given his “Cogito ergo sum”? So, what was Descartes’ method?
Descartes reproaches many researchers of his time and before him for working unsystematically. In this way, it is impossible to arrive at truth. True knowledge can only be attained by means of a method, that is, “sure and easy rules which are such that the one who scrupulously applies them can never hold anything that is not true to be true, and which lead without useless attempts step by step to true knowledge”. In his posthumously published and unfinished Regulae ad directionem ingenii, Descartes tried to design a method for systematically acquiring knowledge. His methodization of the process of acquiring knowledge has been so important for the development of the theory and practice of scientific research that he is considered the founder of modern epistemology. With Descartes, method became an instrument for the discovery and construction of knowledge and thus the foundation of knowledge itself. No longer are new insights placed within traditionally accepted frameworks, but new frameworks are developed for new insights in a way that is still common today.
What was Descartes’ approach like? As is well known, Descartes, in his attempts to systematize knowledge acquisition, first went in search of an indisputable starting point of knowledge. This led him to his “Cogito ergo sum”, I think therefore I am. Subsequently, Descartes wondered what was the certainty that this “cogito ergo sum” was true, and he came to the conclusion that this could only be the case because he saw it very clearly. Therefore, he assumed as a rule: “The things we see very clearly and distinctly are all true”. From this starting point, Descartes’ method aims to acquire knowledge by reducing existing and new insights or sensory impressions to or converting them into clear and distinct knowledge and deriving this knowledge from other clear and distinct knowledge. These derivations must also be clear and distinct. Descartes describes these concepts as follows: “I call clear that which is present and manifest to an attentive mind: just as we say we see objects clearly, when being present they act strong enough..., and our eyes are disposed to look at them. And distinct, that which ... is so precise and different from all the others, that it only comprises what appears clearly to the one who considers it as it should.” Open and therefore not prejudiced, attentive and therefore concentrated are the central concepts. Something can be clear without being distinct, but something that is distinct is always clear.
The next steps consist in what Descartes calls “analysis” and “synthesis” of the available data. The instruments for this are insight or intuition (intuitio), which is the correct sensing of reason that something is indubitable, and deduction (deductio). Both are functions of the mind (intellectus).
The first stage of building a theory of “chains of reasons” is analysis: the dissection of the problems to be investigated into their simplest elements, which can no longer be subdivided. One must study these simplest elements until one knows them distinctly and clearly, that is, one must distinguish them from other elements, and also in such a way that one knows them evidently as they are. In principle, these elements are known in themselves and one can never know them in a wrong way, but the problem is to distinguish them. Although the elements must be known absolutely, and not as things relative to others, it is not a question of knowing the elements merely in such a way that they can be arranged according to their essence, but of knowing how one can be derived from the other, either directly or through the intermediaries of other elements. In this way, if problems arise in the investigation, it is possible to see immediately which elements should be studied first and in what order. It is important not to study more at the same time than one can see distinctly. Sometimes this is not possible, because the chain of inferences is too long and memory fails us. Then one must think through this chain carefully and without interruption as often as possible, until one has a grip on it and one does have this overview. Descartes calls this approach enumeration or induction. If one has established a chain of deductions with the help of induction, one has a true insight (verus intuitus) into the interrelated matters. If, however, one does not succeed in gaining a complete insight into the chain, so that one cannot suffice with “a single insight” (unicus intuitus), then seeing the connection of a link with the nearest links must be sufficient.
The second phase of theory construction consists of synthesis, a process that is the opposite of analysis. It is a question of recovering the problem that has been unravelled by analysis as a whole, but now in such a way that it is clearly and distinctly seen as a deductive connection. Through synthesis, the elements that had been detected through analysis are placed back in the original context of the problem, so that the elements are no longer seen separately but simultaneously. In fact, the process of synthesis consists of an interaction and combination of intuition, in this case the insight gained through analysis, and of enumeration, through the establishment of deductive connections between the different parts of the problem. The difference between the situation after the completion of the synthesis and that before the execution of the analysis is that the problem that was still confused before the analysis is considered as a whole after the synthesis. This oversight is one goal of synthesis. Another goal is to see the connection that exists between the different parts of the problem, even if the individual parts consist of different elements. Only in this distinct view of the composition of things from the elements, so Descartes, does science and with it certain and clear knowledge exist.
In summary, one can say that analysis and synthesis are inverted methodical processes. To solve a problem, one starts with analysis, which consists of establishing deductive relationships by induction (enumeration). This gives one insight (intuitus) into the elements of the problem. Through synthesis, the original coherence of the problem is restored. From the insight gained through analysis, the connection between the parts of the problem is induced by establishing deductive relationships. In other words, analysis is the process of discovery and synthesis is the subsequent evidentiary procedure. Descartes did not see his method as limited to the natural sciences, but as the universal method for all sciences, including the moral sciences, the forerunners of the modern social sciences. Today, analysis and synthesis are common steps in a research process, but in Descartes’ time his ideas were revolutionary because they went against the practice accepted until then. They gave the emerging modern science a methodical basis. His approach questioned the idea of authority that defined scientific thought in the Middle Ages, namely the authority of the church’s official doctrine and that of classical authors such as Plato and Aristotle. Descartes’ contemporary Galileo had become a victim of this idea of authority. By giving the mind the lead in the acquisition of knowledge, the final decision of what knowledge is is no longer in the hands of a higher authority such as the church or tradition, but in that of the individual.

Sources
- Descartes, René, Discourse de la Méthode suivi des Méditations.
-           –           , Regulae ad directionem ingenii. Texte critique établi par Giovanni Crapulli avec la version hollandaise du xviième siècle. The Hague: Martinus Nijhoff, 1966.