Holistic materialism in 20th century physiology, or: How do you get something for
nothing just by being exceedingly complex?

From the time of René Descartes, who in the mid-17th century introduced the idea
that animals functioned like machines, biologists fell broadly into one of two camps:
mechanist and vitalist. Mechanists shared with Descartes the faith that all of biology
could be revealed ultimately by invoking only the laws of chemistry and physics.
Vitalists, in contrast, believed that a ‘vital force’ was imposed on the material substances  of all living organisms. Some believed that, in principle, the nature of the vital force  ultimately could be revealed, whereas the hard-core vitalists believed that the nature of  the vital force is forever unknowable.
In the 20th century, strict mechanism has evolved into something more subtle.
“Holistic materialism”, though rejecting the concept of a “vital force”, proposes that the
essence of “living” emerges, in an ill-defined way, from the incredible complexity of the
metabolic repertoire. Following a short introduction, in this lecture I shall first consider
some work by Jacques Loeb, perhaps one of the last dyed-in-the-wool mechanists, who
in 1918 published the provocative, Forced Movements, Tropisms and Animal Conduct.
Then in contrast, I present some contributions by two other famous American scientists
who were champions of the holistic materialism philosophy: Lawrence J. Henderson
(buffer systems in chemistry and biology) and Walter Bradford Cannon (homeostatic role  of the adrenal gland/sympathetic nervous system axis). Perhaps we shall end up
agreeing with Garland Allen (Life Science in the Twentieth Century, John Wiley, 1975.)
that “…no understanding of the real world could be complete without developing
methods for studying the interactions of components in any system.”