As a physiologist I must acknowledge my limitations. It is enough of a challenge for a physiologist to contemplate the brain in all its complexity and wonder about the interplay of the mind and brain.

Descartes provided a watershed in our thinking about human nature, in stating that there were mechanisms which could be described for the body and the brain as realms for scientific investigation, but the mind and soul were something else.

Concepts of spirituality go even further beyond the limitations of science, into realms of intuition and complex insights and values.

Apropos of these thoughts, I was reading a dictionary entry for an interesting thinker, Maine de Biran (1766&emdash;1824). His life's aim was to produce a major work on the science of man. He was not able to produce such a major work but he developed some seminal concepts which proved to be the forerunner of later scientific movements.

At the end of his life he was critical of his writings as being too schematic and too limited. Interestingly, this is a criticism one can level at science, although science is important for its powerful testing of ideas, and its discipline on the human mind to be rational as far as possible.

De Biran acknowledged that his work, similar to that of science, ignored the religious and social dimensions of human existence.

Nevertheless, one aspect of de Biran's work impressed me. He recognised the importance of introspection as a tool of science. It leads to important observations&emdash;exactly the tool that FM Alexander used in his observations.

De Biran noted the importance of 'the will', of 'willed action'. In this concept lay the understanding of human psychology. The mind operates on the body by 'willing' action. Muscular activity occurs as a result of the mind 'willing' an action. The mechanisms for bringing about the muscular activity are entirely sub-conscious.

The mind 'wills' an action, and this leads to a circuit that calls on programs at lower levels, which then return to the cortex, to activate the nerves that will act on the neuromuscular mechanisms which will bring about the activity.

One could say that we are prisoners of our sub-conscious with the programs that are laid down there. One could say that&emdash;but it need not be true.

As Alexander discovered, it is possible to bring about alterations in those sub-conscious programs by bringing to consciousness the normally sub-conscious inputs from the muscles and joints, the proprioceptive inputs. Inhibiting the output of the programs enables more appropriate programs to emerge.

Maine de Biran was not able to bring spiritual concepts into his scientific description of human nature. Science does have its limitations, although it is a safeguard against irrationality. Nevertheless, de Biran established a line of investigation, introspective observation, that was used so outstandingly by Alexander in his observations on the interplay between the mind, the brain and the body.

Dr David Garlick