The 21st century is and will continue to be undoubtedly the century of Biology. When James Watson and Francis Crick discovered the double helix structure of ADN in 1953, that was the kick-off for the desciphering of the so-called “Book of Life”, a long sequence of six thousand millions of four letters, A, C, G, T, which was completed only fifty years latter. Today, the study of the role of genes in our behaviour has been accompanied by progress in studies about the functioning of mind. Although in the antiquity the analysis of mind constituted an exclusive fief of philosophers, the human mind is now the main subject of analysis for neurologists and psychologists, who share with philosophers the interest in the mechanisms applied to human intelligence. Logicians, mathematicians and computer engineers have also tried to develop these mechanisms artificially up to the same point under the wide project of Artificial Intelligence (expert systems, robotics, artificial life...).

In any case, all professionals converge, be they in a natural or artificial direction, in the same project: to explain the functioning of human mind in order to solve its problems and to widen its capacity (or to develop an alternative intelligence, that is to say, an artificial one).

Until almost the second half of the 20th century, all investigators who approached human mind found important difficulties. The first one, their own prejudices in relation to the purity of rational mind (something practically divine and with no relation with corporal aspects); the second one, the comprehension of the neuronal structure (initiated by Cajal) and its genetic basis; the third one, the difficulty in studying the brain when functioning (problem solved today with scanning techniques). But it has not been until recent decades that there has been a crucial discovery: the rational processes are profundly linked to emotional processes. The rational mind is in fact an emotional mind.