How we learned to stop worrying and love philosophy of science: “physics envy”
revisited
Andrew E. Forbes†1, Anthony R. Ives1, Bradley J. Cardinale1,2, Chad T. Harvey1,
Matthew R. Helmus1, Kelley J. Tilmon1,4 and Christopher K. Williams1,3
1University
of Wisconsin-Madison, Department of Zoology
430 Lincoln Dr.
Madison, WI 53706
Present Address:
2University
of California-Santa Barbara, Department of Ecology, Evolution and
Marine Biology, Santa Barbara, CA 93106
3University of Delaware, Department of Entomology and Wildlife Ecology,
Newark, DE 19716
4South Dakota State University, Plant Science Department, Brookings, SD
57007-1096
†Corresponding
Author
e-mail: aeforbes@wisc.edu
phone: (608)-262-9226
Abstract:
If one chooses to believe the strict definitions of some philosophers, over eighty
percent of what ecologists publish is not actually “science.” As practicing
ecologists interested in justifying our salaries, we beg to differ. The concept of
ecology as a “less scientific” science has manifested itself in the last several
decades as “physics envy.” Here, we argue that the premises underlying such
jealousy are false, and that debating ecology’s scientific merit is a misuse of our
collective energy. Instead, ecologists need to begin more productive dialogues
about their philosophies of science. Ruminations on physics envy are based in
part on false assumptions about physicists’ activities. They are also rooted in
attempts to compare two disciplines that not only differ in very concrete ways, but
are also each internally diverse well beyond any simple stereotypes. We feel
that the perceived inadequacy of ecology that underlies physics envy – the notion
that our discipline has been unsuccessful and unscientific– is unfounded. Here,
we offer our opinion of physics envy, along with results of an informal survey, in
hopes of putting this term to rest.
Background
“Physics envy” is best described as the desire of some ecologists to make
explanations of ecological phenomena conform to the supposedly more
straightforward standards of the physical sciences. This concept is evident in
some ecological texts:
“There is a widespread belief that ecology is different from physics
because (1) it lacks general laws, and (2) it is not a predictive (and,
therefore, not a “hard”) science.” (Turchin 2003, p. 18)
Thus, the relative quantitative rigor, predictive power, and generalizability of
ecological research are concerns for those ecologists suffering from this malady.
The argument for changing ecologists’ methodologies to make them more
scientific dates to at least the seminar paper by Platt (1964). Platt argued that
scientists needed to adopt “strong inference,” a scientific method superior to all
others. This involves:
“1) Devising alternative hypotheses
2) Devising a crucial experiment (or several of them), with
alternative possible outcomes, each of which will, as nearly
possible, exclude one or more of the hypotheses;
3) Carrying out the experiment so as to get a clean result [and]
1’) Recycling the procedure, making subhypotheses or sequential
hypotheses to refine the possibilities that remain” (Platt 1964)
Platt’s paper was successful in so far as many scientists refer to this scheme as
THE scientific method. This is not the only legacy of Platt’s paper. In holding up
molecular biology and nuclear physics as examples of “healthy” sciences (those
using his preferred methodology) while stating that many other disciplines “are
sick by comparison,” he set the stage for major introspection among ecologists.
His denigration of collecting extensive data sets (Platt mentions “surveys” and
“detailed studies” as if they were dirty words) furthered some ecologists’ sense of
unease and tendency towards navel-gazing.
The discussion set in motion by Platt is ongoing (MacFadyen 1975,
Simberloff 1983 and Simberloff 2004). Some ecologists have bemoaned our
discipline’s preference towards exploring system-specific details and
eccentricities over seeking unifying themes (Murray Jr. 1992). Others point out
that these generalities do exist in ecology, regardless of the importance that our
professional community does or does not ascribe to them (Turchin 2001).
Our Opinion
Like most debates requiring introspection, we feel there are nuggets of wisdom to
be gleaned from discussions of physics envy. Three previous ideas stemming
from the debate have been positive developments for scientists. First, Platt’s
(1964) method of “strong inference” is a powerful way to address some, although
certainly not all, scientific questions. This explains its prevalence in high school
textbooks (Balzer et al. 1983, Alexander et al. 1986, Kaskel et al. 1988).
Second, in order to maintain healthy research programs, it is important for
scientists to consider the efficacy of their approaches, something this debate
encourages. Third, regardless of what any ecology-bashers argue,
generalizations really do exist in ecology, and encouraging scientists to uncover
them will inevitably lead to progress.
However, the larger discussion appears to us simplified to the point of
being cartoonish. Most (if not all) scientists use multiple approaches in their
research. Ecology is a prime example of this. Discussions (particularly among
science educators) of the need to adopt THE scientific method are potentially
damaging if they hinder our ability to instill future generations with the creativity
necessary to be successful ecologists. Furthermore, the gap that some
scientists perceive between ecology and physics is meaningless in light of the
diversity of each discipline. While numerous physicists strive to produce
generalizable results (or “laws”), there are ecologists doing the same. Likewise,
not all research in either discipline consists solely of making generalizations or of
using any specific methodology. Thus, while we acknowledge the value of
asking how we do science, we agree with Weiner (1995) that this is best done
without comparison to physics, or any other discipline.
A Survey
Methodology
To examine ecologists’ philosophies of science, we designed a short, informal
survey, unapologetically violating Platt’s stricture of good science. The survey
involved polling 80 physicists and 66 ecologists at the University of WisconsinMadison on: (1) their own work and (2) their perceptions of physicists and
ecologists in general. This allowed us to compare the methodologies of
stereotypical scientists to reality. The survey focused on three areas related to
the issue of physics envy: (1) the degree to which research programs are
quantitatively driven, (2) the importance placed on generalizability (or “laws”),
and (3) the reliance on mutually exclusive alternative hypotheses.
Results-Survey Questions
Our survey indicated clear differences in the way “average” physicists and
ecologists conduct research. Physicists and ecologists agreed that physics is the
more mathematically rigorous (as opposed to qualitative) discipline. Scientists
also largely agreed that physicists are more likely than ecologists to use laws to
explain phenomena; this was supported by scientists’ reports on their own
activities (Fig. 1).
However, misperceptions do exist. Concerning the concept of “strong
inference” (i.e. alternative hypotheses), there was agreement among ecologists
and physicists; 45% of respondents, be they ecologists or physicists, agreed that
ecologists routinely used this scientific method. Just under 70% felt that
physicists did so. Being good scientists, we did a proper statistical analysis and
found that in reality, there’s no significant difference in the practice of the two
groups. Roughly 40% of scientists from both disciplines surveyed said they
routinely formulate alternative hypotheses as a way of conducting science (Fig.
2).
Results-Written Comments
When we sent out this survey, we were interested in gut responses, and so we
asked provocative questions without giving much preamble as to our objectives.
We allowed room for open-ended responses, and not surprisingly received some
rather thorough and often irritated comments.
A lot of participants, particularly physicists, commented on our use of the
term “law.” Several of them chastised us, or offered their own definitions or
amendments in their responses. This is what we expected; a friendly physicist
had warned us about this beforehand. Here are some of the responses we
received:
“I find the ‘pigeon-holing’ inherent in this survey hard to deal
with, as I do the use of the term ‘law’.”
“I don’t like the choice of the word ‘law’.”
“What is this ‘LAW’ that you are talking about?”
We decided to determine who was commenting on our usage of “law” and
found that physicists were more likely than ecologists to mention laws in the
open-ended response section of our survey, 15% to 9% (t-test, p<0.03). This
difference likely stems from many ecologists’ discussions of whether their
science has “laws,” leading to a greater familiarity with such informal use of the
term.
We also noticed that some participants often appeared annoyed with our
survey:
“In a word idiotic… I regret taking it.”
“Seems a bit silly. Hard to comment on.”
“Lacking a quantitative definition of qualitative, I’m rather at a
loss.”
In order to test whether there was any pattern in which participants
showed irritation with us, we developed an index to quantify the “snarkiness” of
respondents. We deployed four panelists to review the survey responses
(without knowing the identity of the participants) and for each of the responses,
they decided whether or not they detected sarcasm in participants’ responses.
When we did a pairwise t-test on the snarkiness indices each panelist generated,
we found that physicists did appear to be more likely than ecologists to take
umbrage at our survey (p=0.063). The explanation for this nearly significant
pattern may be that physicists, unlike ecologists, do not spend much time trying
to compare themselves to researchers in other fields. This would explain why
they were confused by the concept of this survey. Ecologists, on the other hand,
due to their self-conscious nature may not have found our study as bizarre.
Discussion
It seems clear from our survey that we are not alone in our frustration with
attempts to compare ecology to other sciences. However, the prerequisites for
physics envy still exist; some scientists hold on to the false assumption that
physicists are more likely than ecologists to engage in what has been described
as the “correct” scientific method. Two clear remedies to this situation exist: (1)
pointing out the invalidity of this belief, and (2) removing the value judgment
attached to particular methodologies. There are many modes of scientific
inquiry, each capable of generating progress in certain situations. There is no
best way to do science.
Ultimately, we would like a better philosophical paradigm for ecologists.
The best start for such a philosophy is to focus on asking the obvious questions
most of us already do: What am I attempting to learn and how can I best reach a
satisfactory level of certainty in my conclusions? Clearly, this can be expanded
upon. But, rather than leaving this to philosophers trading in technical and
absolutist terms too abstract for most practicing ecologists to bother with, we
suggest this is something best left to each ecologist individually. This will lead to
something far more useful than trying to impose our understanding of others’
philosophies of science to our work, and might make us feel better about
ourselves as well.
References
Alexander, P., M. J. Bahret, J. Chaves, G. Courts, N. S. D’Alessio. 1986. Biology.
Silver Burdett Company, Morristown, NJ.
Balzer, L., P. L. Goodson, I. L. Slesnick, L. Lauer, A. Collins, G. M. Alexander.
1983. Life Science. Scott Foresman and Company, Glenview, IL.
Kaskel, L., P. J. Hummer Jr., L. Daniel. 1988. Biology: An everyday experience.
Merrill Publishing Company, Columbus, OH.
MacFayden, A. 1975. Some thoughts on the behaviour of ecologists. Journal of
Animal Ecology 44: 351-363.
Murray, B. G. 1992. Research methods in physics and biology. Oikos 64:594596.
Platt, J. R. 1964. Strong Inference. Science 146:347-353.
Simberloff, D. 1983. Competition theory, hypothesis-testing, and other
community ecology buzzwords. American Naturalist 122: 622-635.
Simberloff, D. 2004. Community ecology: Is it time to move on? American
Naturalist 163: 787-799.
Turchin, P. 2001. Does population ecology have general laws? Oikos 94:17-26.
Turchin, P. 2003. Complex Population Dynamics: A Theoretical/Empirical
Synthesis. Princeton, NJ: Princeton University Press.
Weiner, J. 1995. On the practice of ecology. Journal of Ecology 83: 153-158.
Figure Captions
Figure 1:
(a) Ecologists’ and physicists’ responses to the statement: “My research is more
concerned with qualitatively describing the properties of a system than in making
quantitative predictions about it.” (b) The same scientists’ responses to the
statement: “In my research, I routinely apply ‘laws’ from my discipline in order to
understand natural phenomena.” Clearly, physicists are more likely to use laws
and be quantitatively oriented than ecologists.
Figure 2.
The top two rows show scientists’ responses to the statement “Scientists in
[ecology or physics] mainly explain phenomena by testing mutually exclusive
alternative hypotheses.” By comparing the left column (responses about
ecology) to the right column (responses about physics), we see that scientists
generally perceive physicists as being more likely than ecologists to use “strong
inference” in their research. The bottom row shows responses to: “My work
centers on explaining phenomena by testing mutually exclusive alternative
hypotheses.” Notice that there is no statistical difference between the actual
behavior of ecologists in physicists, in contrast to the perceived gap in
methodology.
Fig 1.
Fig 2.