Most students of biology are well aware of our humble
beginnings as puny, single-celled lifeforms. The mechanism of our remarkable
transformation was famously described by Charles Darwin in his groundbreaking
text On the Origin of Species,
published in 1859. In many respects, Darwin’s magnum opus was just the opening
chapter of a much broader discussion of how we humans have taken our current
form. Darwin elucidated only a general process of adaptation and evolution in
the face of environmental pressures. He left his successors with the more
onerous task of applying this rule to the tortuous history of human evolution. Rising to the occasion nearly a full century later was Homer
Smith, a prominent kidney physiologist who spent much of his life and career as
the Director of Physiological Laboratories at the NYU School of Medicine. Dr.
Smith shares his account of our evolutionary history in his 1953 book From Fish to Philosopher. In the book,
he posits that organisms must have a system for maintaining a distinct
“internal environment” in order to have any sense of freedom from the
perennially dynamic external environment. He guides the reader through the various
biological filtration devices that have come and gone over the eras,
culminating with the fist-sized organs dangling next to our spines.
The book is often billed as a detailed treatise on how
modern-day mammalian kidneys have arisen from their more primordial forms – a
fair assessment, especially given the author’s background. But this book offers
readers something much more ambitious in scope than a rehashing of his work in
renal physiology. For example, the first chapter of the book, “Earth”,
highlights geological milestones that molded the early environment of the first
known lifeforms. In Dr. Smith’s words,
“the history of living organisms
has been shaped at every turn by earth’s vicissitudes, because every geologic
upheaval, by causing profound changes in the distribution of land and sea, has
had profound effects on the climates of both, and hence of the patterns of life
in both” (pp. 9).
By the final chapter, “Consciousness”, he has begun to
ponder questions of metacognition and learning. He marvels at how our complex
nervous system has allowed classical pianists to balance the rigidity required
for technical prowess, and the fluidity required for creativity. This is not a
textbook about our kidneys. From Fish to
Philosopher is a story of mankind’s genesis, told through the existential
musings of a physiologist who left no stone unturned.
