Great Geologists | 73
T. C. Chamberlin
“Is geology an art or a science?” I was posed this question
during my recruitment interview with the Chief Geologist
of the supermajor that I worked for in the early years of
my career. The question may seem odd to many. Geology
is obviously a science, isn’t it? I presumed my interviewer
was hinting at the need for creativity in interpretation of
geologic data. But how geology functions as a science is
a question that has intrigued many including, arguably the
greatest American geologist of his age, Thomas Chrowder
Chamberlin.
Karl Popper suggests that the scientific method is based on
the premise that a simple, unbiased observation promotes
a hypothesis to explain it. This hypothesis can be tested
by experimentation and further observation which can
falsify it, with the emphasis on falsification. In practice,
much of geological science does not follow this process.
Rather a hypothesis gathers support from observations
— geoscientists view data in the light of the hypothesis
they particularly support, often linked to their experience.
Consider, for example, the competing hypotheses of a
contracting Earth and plate tectonics to explain mountain
formation as debated in the 20th century. There may
always be an element of bias as hypotheses gain support
or are refuted. Indeed, some view this as a good thing. “No
progress without prejudice” remarked A.F. Buddington, the
great Princeton petrologist, meaning that championing a
hypothesis helps gather important data and spurs our science
forward.
In 1890, Chamberlin published on “The Method of Multiple
Working Hypotheses” — a landmark and still-cited paper.
He encouraged geologists (indeed all scientists) to carry
multiple explanations for their observations in their minds and
weigh then equally until further observations promoted one
above all others. So, to explain a sedimentary breccia deposit
observed in the field, mass transport, faulting or dissolution
of matrix sediment, are all equally plausible explanations until
T.C. Chamberlin from an 1897 photograph.
Photographer unknown.
definitive evidence is observed. We should, he argued, avoid
bias from the guidance of a “ruling theory”. Such an innocent
approach is probably implausible in practice. We interpret
rocks through the lens of our experience. Nonetheless, it is
obviously good scientific practice to keep an open mind.
Chamberlin was very much more than a scientific theorist.
He was an exceptional field geologist who recognised
the record of glaciation in the American landscape and
Pleistocene sedimentary record. Somewhat ahead of his
time, he considered the role of atmospheric gases in climate
change and their sequestration in the rock record. He also
developed a theory for the formation of the Earth linked to
the tectonic processes responsible for mountain building,
sea-level change and the subdivision of the geological record!
In his own words, he sought to explain “the very soul of
geologic history.” He was also an excellent teacher, writer
and academic administrator and began publication of the still-
influential Journal of Geology.