More historical
background…this, concerning how our conception of life has progressed from
vitalistic to mechanistic—from the “life
force” of Aristotle’s time to “living things as machines” (which is by and large
the current view). This section delves into the way things have played out historically,
leading to a manner of perceiving nature that has, collectively, left us
somewhat blasé about its countless wonders. The contemporary scientific-based
worldview has not only removed any reason to feel anything akin to reverence
for nature, but has created a sense that life’s mysteries have mostly been
solved…or inevitably will be. And these are precisely the sort of notions I’m
attempting to dispel by providing what I believe is a more balanced perspective.
The section following this one, “Part VII: Why Do Things Have To Be So
Complicated?” looks into the astonishing and seemingly boundless complexity
found throughout the natural world—and why it’s so important to not take this
inherent attribute of life for granted.
VI.
The Day Vitalism Died
Up
until 1953 it was still possible to believe that there was something
fundamentally and irreducibly mysterious in living protoplasm. No longer. Even
those philosophers who had been predisposed to a mechanistic view of life would
not have dared hope for such total fulfillment of their wildest dreams.
Richard Dawkins, River Out of Eden
Late in his life, Jacques Monod asserted during an
interview, “Anything can be reduced to simple, obvious, mechanical
interactions. The cell is a machine; the animal is a machine; man is a machine.”
How did the mechanistic viewpoint come to dominate biological thinking to the
extent that a world-famous scientist could make such a manifestly
one-dimensional statement? As always, turning to history is a good place to
start looking for an answer.
Beginning around Aristotle’s time (4th
century B.C.), philosophers believed that the orderly way in which organisms
grow and develop could be credited to a vitalistic principle, an influence that
was beyond human comprehension and thus considered not within reach of investigation.
This vital force was a manner of
identifying the cause behind a prevailing worldview which, in pre-Christian
times (and with roots going back at least as far as ancient Egypt), could
broadly be considered pantheistic.[1]
As the scientific revolution gathered steam it
increasingly became apparent that most observed phenomena were completely
natural and could be understood and described without invoking mystical forces.
(Well into the 19th century, in certain fields—embryology, for
instance—the intermingling of naturalistic and supernatural explanations was
still practiced by reputable scientists.) Galileo, Kepler, and Newton in turn
demonstrated the inestimable worth of mathematics as a way of describing the
cosmos, which contributed to an even more compellingly mechanistic worldview.
Ernst Mayr, in his last book, This is Biology
(published when he was ninety-three) describes the intellectual mood of
this era:
The rapid development of physics…after [the
Renaissance] carried the Scientific Revolution a step further, turning the more
general mechanicism of the early period into a more specific physicalism, based on a set of concrete
laws about the workings of both the heavens
and the earth…. The physicalist movement had the enormous merit of refuting much of the
magical thinking that had generally characterized the preceding centuries. Its
greatest achievement perhaps was providing a natural explanation of physical
phenomena and eliminating much of the reliance on the supernatural that was
previously accepted by virtually everybody. If mechanism, and particularly its outgrowth into physicalism, went
too far in some respects, this was inevitable for an energetic new movement.
Substantial numbers of people who cared deeply
about such matters clung to an enduring intuitive sense that living things
possessed qualities that could never be accounted for by physicalism (defined
as the belief that physical entities are all that exist). A sort of
countermovement—described collectively as vitalism—resulted,
manifesting in different forms at different times. This philosophical vitalism originated in the 17th century
and held sway until the mid-1800s. Though never a unified “movement,” it was a
reaction to mechanism, and its proponents focused on various issues they felt
physicalism failed to take into account: the origin of adaptations and
behaviors, the mystery of development and regeneration…the very nature of what
animated living things.
Contrary to how naïve any vitalistic theories
appear today, vitalism in its time was a legitimate alternative—not just to
mechanism, but to the more sophisticated physicalism as well. Adherents of both
schools were passionate in their beliefs and there were repeated periods of
struggle between the ideologies. After all, physicalists of the mid- to late-19th
century employed their own nebulous concepts and poorly defined terms to describe
phenomena that could not yet be understood. In addition, they often failed to
address the main concerns of their intellectual adversaries.[2]
However, with unrelenting scientific
advances, vitalism gradually faded into the background, in large part due to
increasingly being seen as a metaphysical program unable to come up with
coherent theories subject to being tested.
The complex history of cytology (the study of cells) encapsulates the transition between a
vitalistic and mechanistic conception of living things—from initial discovery,
through all the steps leading to an understanding of the cell’s central place
in nature.
Cells were unknown before English polymath Robert
Hooke, peering through an early microscope at a thin slice of cork, saw tiny and
apparently empty four-sided compartments that reminded him of monks’ cubicles.
Hooke had no idea what these minute chambers were but certainly wouldn’t have
imagined he was observing the building blocks of all living things. Early
microscopists were still influenced by a holdover from ancient Greek
philosophy—atomism—and assumed that
the basic constituents of life were invisible, indivisible, indestructible
particles. (Not to be confused with the modern, scientific conception of atoms.)
By the end of the 18th century it was an
accepted fact that cells were the fundamental components of plants but it
wasn’t until the 1820s that French botanist Henri Dutrochet first proposed that
they were not just structural entities but physiological as well. Owing to his
discovery of osmosis[3]
and careful studies of respiration,[4]
Dutrochet is considered the father of cell physiology. A confirmed
anti-vitalist, his work was always focused on demonstrating that physics and
chemistry lay behind life processes.
Dutrochet’s work led to a more wide-ranging cell theory that was independently put
forward by two Germans: botanist Matthias Schleiden and a colleague, zoologist
Theodor Schwann. In 1838, Schleiden proposed that all parts of a plant were
composed of cells and that new cells arose from the nuclei of older cells,
which were formed in some sort of unspecified crystallization process. (While
the gist of Schleiden’s premises were correct, almost all the details were
based on erroneous speculations.) The following year, Schleiden and Schwann had
a discussion involving plant cells’ nuclei. Schwann recalled having observed
similar structures in tissues from frog embryos.[5]
Recognizing an important finding, they compared resemblances and confirmed a
connection between the two phenomena. Schwann realized that animals as well as
plants were composed of cells and that cells—not
organs and tissues—were the elementary units of life. Shortly thereafter he
published a paper on his ground-breaking hypothesis. Ernst Mayr: “Few publications
in biology have ever caused such a sensation as Schwann’s magnificent
monograph. It demonstrated that animals and plants consist of the same building
blocks—cells—and that a unity therefore exists throughout the entire organic
world…. It was a vigorous endorsement of reductionist thinking.”
By 1852, after years of painstaking observation,
the Polish embryologist Robert Remak
concluded that binary fission—that
is, dividing in two—was the only means by which animal cells could multiply. He
established without doubt that new cells were not the result of productions of
the nuclei or unformed substances in intercellular spaces (the erroneous
hypotheses of Schleiden and Schwann, respectively). His investigations, while
slow to gain acceptance, paved the way to an entirely new model of how
organisms developed. Unacknowledged in his lifetime (and even to this day), it
was Remak’s work that helped clarify the muddled views surrounding animal
cells’ origins.
Eminent pathologist Rudolf Virchow, after having
initially been skeptical of Remak’s
findings, became an enthusiastic supporter. (Virchow famously popularized the
Latin aphorism, Omnis cellula e cellula—“Every
cell from another cell”—a motto that is permanently associated with his name.) By
the mid-1850s, in addition to authoring an influential book on pathology, a
series of well-received lectures by the charismatic scientist helped lead to
wider acceptance of this new cell theory—further eroding belief in spontaneous generation, which still
held sway at the time. Virchow was an outspoken advocate of mechanism and early
promoter of the concept that life is essentially a mechanical process. His
popularization of these ideas helped expand research into the finer details of
cell division, which was then being greatly aided by improved microscopes and
novel staining techniques.[6]
Biologist Walther Flemming studied the process of
cell division and, thanks to the new staining methods, was the first person to
see threadlike structures (later to be named “chromosomes") in the nuclei
of cells taken from salamanders. Flemming observed these “colored bodies” and their
distribution in daughter cells, naming this process (mitosis) in a detailed
report of his findings in 1879. Though unable to actually witness the chain of
events, his important book, Cell
Substance, Nucleus and Cell Division, published four years later, provided
the first definitive account of cell division. Also of note is that Flemming—in
common with all his peers—was unfamiliar with Gregor Mendel; otherwise, he may well have perceived the
link between chromosomes and heredity. (As it turned out, two decades passed
before the re-emergence of Mendel’s investigations revealed the significance of
Flemming’s own important discoveries.[7])
At the beginning of the 20th century,
cell theory had achieved a degree of coherence: it was recognized that both
plant and animal tissues are composed of cells; that new cells arise through
binary fission; that all organisms start out as a single cell formed by the
union of egg and sperm; that these germ
cells each carried a set of hereditary elements, or factors (later, genes); that these factors were duplicated during
cellular division, becoming two identical sets of genetic material
(chromosomes); and that each new cell thus received a copied set of factors
from the parent cell. It was a start.
The physicalist viewpoint was further bolstered by
the discoveries of German-born physiologist Jacques Loeb. In 1891 Loeb
immigrated to the United States where, along with several successive
professorships, he taught physiology (while also conducting research on various
marine invertebrates) at the now-famous biological laboratory in Woods Hole,
Massachusetts.[8]
Already long committed to a “biological engineering” approach in his
experimental work, Loeb’s landmark book, The
Mechanistic Conception of Life, published in 1912, described experiments
involving sea urchin eggs whose development he was able to induce without their
first being fertilized; his results (initially attained in 1899) provided
dramatic evidence supporting the mechanistic model of cellular functions. This
procedure later became routine, but in those simpler times his results created
a sensation; newspaper headlines all but claimed that Loeb could create life in
a test tube.[9] He
became one of the most famous scientific figures in America, and was
influential in helping biology transition to a largely experimental
science.
Mendel’s recently exhumed research results provided
solid evidence that heredity was indeed controlled by molecules, providing a
significant boost to Loeb’s (and other
committed mechanists’) investigations. And it was Loeb who insightfully recognized that Mendel’s
findings pointed the way to biology’s next big mission: to discover the
chemical substances within chromosomes that were responsible for passing on
hereditary traits. Though it may have taken longer than expected, biochemists
James Watson and Francis Crick made a monumental breakthrough in the early
1950s that would all but finish off vitalism. Boyce Rensberger noted that “by
applying a purely reductionist approach to the study of life, they would
vindicate the mechanist view spectacularly with the discovery of…DNA and the
cracking of the genetic code.”
That tremendous leap forward captivated the
literate world. It epitomized science at its best and what a new breed of
scientists were capable of and, regardless of their level of comprehension,
everyone was talking about the wonderful double helix. A torrent of breakthroughs followed, along
with increased research funding and the development of truly impressive new technologies. Thanks to enthusiastic
media attention, in addition to popular books written by intriguing
men-of-learning, the public was led to a widespread and virtually unquestioned
perception of cells as tiny machines—very complicated machines, yes, but
comprehensible nonetheless.
In addition, by the latter half of the 19th
century, science had assumed an aura of authority that complemented the climate
of those times. A new picture of reality emerged that attested to a world operating by
simple, rational laws: predictable, reasonable, and comprehensible (even if
this was not always strictly the case). Importantly, it was a reality no longer
seen as inherently
mysterious—somewhat like the Newtonian world-view, but a version charged with
new power and accessibility through being extended to encompass the study of
life. The establishment of relativity,
Heisenberg’s uncertainty principle,
and quantum theory injected mystique
back into the universal view but their effect did little to dent a new confidence
in Earth-bound empirical science.
The announcement of DNA’s discovery via a two page
article in the April 1953 issue of Nature
began a whole new chapter of modern life; from a cultural standpoint,
science’s role in everyday living was a perfect addition to the atmosphere of
optimism and progress following WW II’s conclusion. Religious views continued
to be influenced by the lasting impact of Darwin’s radical ideas; as his theory
of natural selection gained ever greater acceptance, people felt the wider effects
of being further liberated from the church’s stifling dictates and lingering superstitions
(a course first set in motion by Newton). Even devoutly religious people saw
the light and were tentatively embracing a perspective that permitted both God and science to illuminate their
worldview. The never-ending introduction of fantastic new machines and
technologies, plus an escalating adoption of mechanical terminology (and,
later, computer jargon) to describe biological processes, lent credence to the
notion that living things are essentially machines as well—a supposition that
has only grown stronger with passing time.
©2016 by Tim Forsell draft 8 Apr 2016
[1] Pantheism is the belief that the Universe (or nature as
the totality of everything) is identical with divinity, or that everything
composes an all-encompassing, immanent god. Pantheists thus do not believe in a
distinct personal or anthropomorphic god. Such concepts date back thousands of
years, and some religions in the East continue to contain pantheistic elements.
[2]
Mayr again: “It is ironic that the physicalists
attacked the vitalists for invoking an unanalyzed ‘vital force,’ and yet in
their own explanations they used such equally unanalyzed factors as ‘energy’
and ‘movements.’ The definitions of life and the descriptions of living
processes formulated by the physicalists often consisted of utterly vacuous
statements. For example, the physical chemist Wilhelm Ostwald defined a sea
urchin as being, like any other piece of matter, ‘a spatially discrete cohesive
sum of quantities of energy.’… [Pioneer embryologist] Wilhelm Roux…stated that
development is ‘the production of diversity owing to the unequal distribution
of energy.’ These [and other] physicalists never noticed that their statements
about energy and movement did not really explain anything at all.”
[3]
Osmosis is the tendency of a solvent—such as water—to diffuse
from a region where dissolved substances are less concentrated to a region
where they are more so. Unless checked, osmosis continues until the
concentrations of the substances are in equilibrium.
[4] The movement of oxygen (from air) to tissues and cells
and subsequent elimination of carbon dioxide (as a waste product).
[5] It should be noted that little was then known about
animal cells; in contrast to plants, it was much harder to prepare animals’
relatively delicate tissues for study under a microscope. Also, animal cells
are typically much smaller than those of plants.
[6] Staining visually enhances specific parts of the
generally colorless cellular interior, by means of a number of chemical agents
and treatments. Their use was first developed by François Raspail, progenitor
of the study of cytochemistry.
[7] Flemming’s identification of chromosomes and mitosis
are considered to be among the 100 most important scientific discoveries.
[8] Loeb’s was the first major discovery to come out of the
Marine Biological Lab (1899).
[9] The press’ coverage of Loeb’s discovery evidently gave
birth to the (mis)use of that hackneyed expression. According to Boyce
Rensberger, “Loeb’s experiments, in a seaside laboratory and on marine
organisms, became so mixed up in the popular mind with the allegedly mysterious
powers of the sea that unmarried women were advised not to bathe in the ocean.
Childless couples, on the other hand, rushed hopefully to beach resorts. Loeb
even received letters from desperate couples asking him to give them a child.”
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