The cognitive revolution in Europe: taking the developmental perspective seriously.

The seeds of the formalization of thought were sown by the French philosopher René Descartes in the 17th century [2]. Descartes argued that thinking is reasoning, and that reason is a chain of simple ideas, linked by applying strict rules of logic. With his ‘cogito ergo sum’, Descartes was the first precursor of cognitive science (even if he was wrong about the dualism of mind and brain). Then, in the 19th century, it was an English mathematician, George Boole, who invented symbolic calculus, in which logical operations like or, and, and if-then are expressed as simple mathematical computations using 0 and 1 [3]. Boole’s dream was to translate all operations of the human mind into elementary mathematics. Part of this dream was realized in the 20th century thanks to the Swiss psychologist Jean Piaget, who showed how elementary psychological mechanisms (mental actions and operations) gradually construct logical and mathematical thinking between infancy and adulthood [4]. This was also shown by the French neurobiologist Jean-Pierre Changeux in his ‘neural Darwinism’, which describes the tight links between logic, mathematics and the brain [5], links we can now observe directly by means of functional brain imaging [6]. It was another French philosopher, Julien Offroy de La Mettrie, who sowed the seeds of the automatization of thought in the 18th century [7]. La Mettrie dared claim that humans were machines (according to Descartes, only animals were so). Based on this premise, he began his mechanistic attempt to naturalize the human mind. This attempt took on a more modern form in the 20th century when the English mathematician Alan Turing imagined a virtual device (the Turing machine) that could translate any humanly computable mathematical problem into a sequence of simple operations [8]. This was the invention of the algorithm, the basis of what was to become computer science and the germ from which artificial intelligence was born.