Philosophy, a discipline without equals, seeks to account for reality, if possible in its entirety. It can be practiced only through the analysis of manifestations as diverse as art, religion, anthropology, politics, etc.

The secret of invention or the art of inventing has recently become the object of positive or experimental research, aimed at discovering the logic of the initial mental processes that lead to “innovation.” But the problem is old and goes back to antiquity: The art of memory, rhetoric, symbolics. Does the succession of thought in invention follow a rule, such that its variations could be classified? Here I offer but a general direction: There is an analogy between the two relations: invention/innovation and fecundation/maturation – namely, a male and a female principle.

The Ancients thought that inventing was a divine art and that man receives the spark to then brood over its fruit in his mind. Today's still dominant materialist tendency insists on the importance of this secondary maturation and minimizes the role of the primordial spark.

Thus becomes possible the ranking according to a unique order — but not without hesitations and guilt — of thinkers as far apart as Mandeville, Adam Smith, Hegel, Buffon, Rousseau, and Herder, to find the contemporary trend to which François Dagognet belongs.

Dagognet's work shows that making algorithmic compressions seems to be one of the major targets of scientific progress. This effort has been so successful that until recently one might have thought everything could be algorithmically compressed. Indeed, this statement, which might be seen as a scientific translation of the Hegelian thesis in its strong form (“the real is rational and the rational is real”), admits to some objective limits in computer science. Though a lot of algorithms are successful, there exist today, and perhaps forever, logical and physical limits that cannot allow us to cherish the dream of a “theory of everything.” Moreover, a complete mastery of complexity does not seem possible — because some domains of reality are too complicated to be computable, because the human brain is too limited, because computers cannot do that much better than the human brain, and because, ultimately, there are some kinds of things it would make no sense to compress. This paper shows that Dagognet's work came to recognize what a glance at the history of algorithmics has made evident.

In this contribution, I argue for epistemological impurity as the key to the historical reconstruction of the proto-biological sciences of the eighteenth century.

The traditional approaches to the more or less complex and more or less stratified past of science either focus on the ideal content of that which has in the meantime been recognized as standard biological knowledge (transmitted from generation to generation by textbooks) or otherwise try to uncover the implicit cognitive principles at work in order to reveal their shortcomings (as measured against today's accepted criteria = epistemological presentism).

A closer look at the breakdown of the classical models of mechanistic explanation and the detailed analysis of the new empirico-experimental research in the neurophysiology of the eighteenth century shows, however, that eclectic procedures of various kinds have dominated the field. This eclecticism (the principle of epistemological impurity) supported, and was in turn supported by, what has recently become known as “thinking with one's hand.” The paper illustrates this specific kind of thinking (and experimental acting) with reference to the case of Nicolas Le Cat's microphysics of nervous activity.