In 1990, the Cité des Sciences et de l'Industrie presented an exhibition on consciousness and thinking: The Enchanted Loom - from the Art of Memory to Neuroscience - , the historical roots of our knowledge of the brain. Passionate interest in the subject has never waned, and recent research continues the questioning that goes back to the dawn of history.

Alcmaeon of Crotona, who lived in the 6th century BC, was the first author in the western world to posit that "what governs" is in the brain. His work was lost very early, yet it exercised a powerful influence. His ideas were adopted by Hippocrates in the 5th century and partly shared by Plato. They were contested by Aristotle, who held that the heart, the citadel at the centre of the human body, was the seat of sensory perception. Several centuries later, Galien showed that impulses travel along the nerves from the brain and studied the action of nerves on muscles. For centuries philosophers, theologians, anatomists and doctors disputed their respective claims to be the only ones entitled to, and capable of, truly explaining thought and feeling, the "passions" that raised so many moral and scientific questions.

The 16th century revolution in anatomy generated a flood of anatomical illustrations: The Fabric of the Human Body by Vesalius, drawings of Leonardo da Vinci.
In the 17th century, Descartes opposed extension to thought, and mind to body, inspiring new research in philosophy and anatomy. La Mettrie did away with the idea of a physical joining point between the mind and the body - the pineal gland for Descartes - positing a brain but no soul in a human machine. Philosophers like Locke and Condillac, considered sensory perception the origin of knowledge; they focused attention on the brain as the centre of sensation, thereby positing its role as the link between bodily states and moral, intellectual and emotional dispositions (Georges Cabanis and the ideologues). Diderot compared the brain to a spider seated at the centre of its web of nerves. Great anatomists of the XVIII century supplied their philosophical colleagues with more and more detailed descriptions of the brain: Vieussens, Willis and later Vicq d'Azyr.

The immense popularity of phrenology in the early 19th century , encouraged belief in the brain as the active center of all knowledge and feeling.
Research into locations of cerebral functions opposed phrenologists such as Gall and Broussais to thinkers like Flourens favoring an integrated view of brain and mental
functions.
The often extravagant theories of phrenology have left their mark with expressions such as "high-brow" culture or the statement "you need your head read". More importantly, related research led to the first identification of the areas of the cortex associated with certain functions. An example is Broca's work on the areas of the brain associated with language.
Brain functions did not interest only anatomists and physiologists. Sensory perceptions and emotions were also fundamental to the development of new ways to look at mankind and the individual.
The grand theories of the history of life on earth and the place of mankind make special reference to sensory perception (Lamarck) or to habits and will (Darwin). Disorders of the brain, on the other hand, inspired psychological investigations into human behavior determined by emotions (Dr Charcot's hysteria patients) or subconscious thoughts (Janet,Freud).

Since the end of the 19th century , practically all the major scientific and technological discoveries have been applied to brain research - from electronics and quantum mechanics to genetics and molecular biology. Research into electricity and biochemistry, and progress in microscope technology, has
provided new tools for research, broadening its scope well beyond the descriptive anatomy of the brain.

The discovery of neurons - the cells making up much of the nervous system - by Golgi and Cajal, followed by the development of new dyes to visualize them, opened the way for detailed research into their structure, properties, functions and connections (in particular the study of reflexes by Sherrington).
For the general anatomy of the brain, Sperry showed the functional difference between the right and left hemisphere of the brain, based on the study of patients with an impaired corpus callosum, while Penfield mapped locations of cortical functions (sensorimotor cortical homunculus). Specific areas of the cortex, of variable size, appears to correspond to each section of the sensory body.

In the 20th century, perception, language, feelings, intelligence and other issues in the philosophy of mind were increasingly treated as natural phenomena, with neurosciences offering the hope of a unified understanding (Churchland) of cognitive sciences. Neurophysiological methods have also been applied to the study of dreams to identify the underlying neuronal structures (Jouvet).

Other theories leave aside the actual physical structure involved in the operations of the mind, taking an analogy with computers as their starting point Turing and cyberneticians).
Still others understand the mind in terms of the body. As early as 1887, William James traced a path from physical behavior to feelings. More recently, Damasio continued in this direction, positing an essential link between the emotions and cognition. Cognition is also affected by the interaction between individuals and their environments, which can even change the structural operation of the brain (theories of neuronal selection Changeux); Neuronal Darwinism (Edelman).

Drawing on the findings of science, some philosophers (Chalmers and Clark) have talked of the bodily nature of thought ("Embodied Cognition") or the inscription of the mind in the body (Varela).

The brain thus continues to attract the interest of specialists in many different fields, but solutions remain problematic.
As we have seen in this brief introduction, many different theories and opinions have been put forward , emphasizing biology or philosophy, materialism and spiritualism to varying degrees. To understand what we know today about the brain and the mind, it is essential to see how biology and philosophy are inseparably intertwined, and how this relationship has come about over time. (Jeannerod).