Reply by the
Author to David Hershey’s comments
Douglas Allchin
Minnesota Center for the Philosophy of Science and
Program in History of Science and Technology
University of Minnesota
Minneapolis MN 55455
allchin@pclink.com
David Hershey echoes here complaints in the
Journal of College Science Teaching 31(May, 2002): 6-7, a journal of the
National Science Teachers Association where
one may also find my earlier replies, including my citations to van Helmont's
original work.
Let the reader not miss my central
theme: that historical context is
critical to understanding how science happens, including experimental
design. Hershey's present-oriented
approach to history (Butterfield 1931) introduces conundrums. For example, Hershey selects Boyle's
criticism of van Helmont—notably over two decades later—to represent
“contemporary” opinion. If so, why did
many individuals at the time (before and including Boyle) repeat the willow
tree experiment and discuss its results and method as significant (Brock 1993,
49-53)? Today perhaps, van Helmont's
concept of 'gas' seems “largely unscientific” and thus irrelevant. How, then, can one appeal to his coining the
term in a scientific context as “founder of pneumatic chemistry”? Is it meaningful to imagine how van Helmont should
have interpreted his results in terms of a modern concept of
gases? Assuming that today's
definitions of “science” or “gas” apply throughout history is problematic. Educators now widely recognize conceptual
change as a feature of science (Kuhn 1962).
Hershey's purpose was “to use a familiar
historical experiment as a basis for a discussion of modern experimental
design.” I consider this anachronism as
misleading about science.
Discuss modern experimental design, yes. The potential sources of error are many indeed and central to
scientific practice (Allchin 2001). But
nothing is gained by applying modern standards critically to an earlier case
based on different norms. Trying to
“correct” the history obscures how science actually happens(ed). If one is not willing to engage historical
context, then do not use history at all.
Pseudohistory—historical facts used piecemeal to prove a point—only
misportrays the nature of science (Allchin 2003a, 2003b).
It would be valuable indeed to understand
how van Helmont could have isolated a substance we now call carbon
dioxide and yet reasonably failed to recognize its role in the tree
growth he also studied. How could he
have been both “right” and “wrong”—by our standards? Merely profiling van Helmont's flaws and/or
faulting him, however, only leads to paradox.
One must get beyond simplistically labeling right and wrong, hero and fool. One must understand van Helmont
himself. This is where the approach
Hershey defends falls short.
Appreciating the context in which van Helmont reasoned from empirical
evidence yet could later be considered mistaken constitutes, in my view, a
profound lesson in the foundations and limits of experimental design and
scientific reasoning (Brock 1993, xxi-xxii).
Regarding Hershey's continuing concern
about being misquoted, I must beg the reader's forgiveness. I used quotes to mark a well-known phrase
being adapted ironically. To those who
missed the irony, I must apologize. I
also wish to thank the Pantaneto Forum for considering my article worth
republishing.
References
Allchin, D. 2001. Error
types. Perspectives on Science 9:38-59.
Allchin, D. 2003b.
Pseudohistory and pseudoscience. Science & Education 12:341-357.
Brock, W. 1993. The Norton History of
Chemistry. New York: W.W. Norton.
Butterfield, H. 1931. The Whig
Interpretation of History. London: G. Bell and Sons.
Kuhn, T.S. 1962. The Structure of
Scientific Revolutions. Chicago: University of Chicago Press.