Experimental Discovery, Data Models, and Mechanisms in Biology: An Example from Mendel’s Work - Mechanism and Causality in Biology and Economics - page 99

amount of discoveries by testing the predictions of a theory. For instance, the
curved path along which light passes through a large gravitational field had been
exactly predicted by the theory of relativity before it was discovered. The history of
science seems to be filled with great discoveries made by confirming the predictions
of overarching theories.
Moreover, a number of philosophers believe that even if an experimental or
observational result is not predicted by any established theory, its recognition is
based on theoretical interpretations. They would suppose that, for example, the
discovery of oxygen was recognized only when Antoine Laurent Lavoisier devel-
oped a new theory of combustion and the elements. If all observational and
experimental results require a theoretical basis, as theory-oriented philosophers
believe, then people might conclude that no discoveries can be made without
theories. Is this true? Are there no discoveries that could be made simply by
conducting an experiment? Could discoveries be made without the engagement
of theories?
To date, philosophers have focused on the role and contribution of theories when
investigating various cases of scientific discovery. Recently, a few philosophers of
science (Hacking 1983 ; Mayo 1996 ; Galison 1998 ; Waters 2004 ) have discussed
experiments in their own right but have paid little attention to the way experiments
lead to new discoveries. By contrast, philosophers who analyze discoveries have
not neglected experiments but have focused mainly on the experimental testing of
theoretical hypotheses rather than the experimental discovery of phenomena or
entities (Schaffner 1993 ; Craver 2002 ; Darden 2006 ). As a result, the problem of
whether there exist experimental discoveries has not yet been explored. Of course,
theory-oriented philosophers may think that recognition of an experimental discov-
ery relies on discovering an explanatory theory. Again, we need to carefully
investigate whether this is so.
The aim of this chapter is to argue that there are experimental discoveries that
could have been made independent of theories. I will explore the questions of
whether there are experimental discoveries and, if so, what counts as an experi-
mental discovery and what the relation is between experimental discovery and the
discovery of a mechanism. Gregor Mendel's work on peas will be taken as the main
example. Frederick Griffith's experiment with Pneumococcus bacteria in mice and
Hans Driesch's experiment on sea urchin embryos will be discussed as foils.
My argument proceeds in the following order: First, I specify problems with the
identification of scientific discoveries and the recognition of the discoverers and the
discovered in Griffith's and Driesch's experiments. Second, I introduce historical
controversies about Mendel's discovery and argue that what Mendel discovered is
two data models extracted from his experiments with peas. Following this argu-
ment, I discuss the relationship between experimental discoveries and mechanisms.
I conclude that an experimental discovery can be identified and recognized by
the following conditions: (1) An experimenter must propose data models to reveal
significant phenomena, (2) no established theories can predict and explain the
phenomena, and (3) the experimenter must envisage searching for underlying
mechanisms for the phenomena, whether or not he or she proposes correct