Biology Reference
In-Depth Information
idiosyncracies of the animate world, (ii) biological laws, if there are any, do
not necessarily apply throughout the universe (since they are domain-specific),
they are not exceptionless, and they are contingent, (iii) the DN-model
appears to refer to a finished and ideal science (Railton, 1978), whereas
biological theories are almost always 'in progress'.
In response to the inadequacy of the DN-model, alternative modes of expla-
nations were constructed (e.g. Railton, 1978; Salmon, 1989). Currently, in the
philosophy of science, there are two mainstream ideas about what counts as a
scientific explanation: the unificationist and the causal/mechanical type of expla-
nation. The first view, which is in many ways a descendant of the DN-model,
also endeavours to unify disparate phenomena observed at different levels of
organization by finding laws at the lower level that together with initial condi-
tions yields an explanation of the phenomenon at the higher level (e.g. Kitcher,
1985). It seeks the unity of science as much as possible, but at the same time it
avoids ending up with a 'theory of everything'. Systems theoretic-oriented sys-
tems biologists in particular emphasize that finding more general principles, if
not laws, is of utmost importance in systems biology; in this sense they are unifi-
cationists (e.g. Hornberg et al., 2005). The second view is the causal/mechanical
type of explanation (Wimsatt, 1974; Railton, 1978; Salmon, 1984; Bechtel &
Richardson, 1993; Machamer et al., 2000; Craver, 2001; Woodward, 2003). This
view is much more widespread in biology. In the next section, we will introduce
this type of explanation. There is no a priori reason though why systems biology
should not engage in both types of explanation, but again this is an issue to be
discussed in this topic.
4.4. Mechanistic explanation
In biology, a particular type of a reductive interlevel explanation, which is related
to the causal/mechanical view of reality, is called mechanistic explanation and
it deserves some special attention as it seems to capture many explanations
found in systems biology. This kind of explanation has long been neglected by
philosophers of biology, but as from 1990 the philosophical interest in mech-
anisms and mechanistic explanations is on the increase. The growing interest
also shows up in this topic, since several authors extensively deal with this issue
(see chapters of Bechtel; Westerhoff & Kell; Richardson & Stephan; Schaffner;
Shulman). The essential difference between a mechanistic explanation and a
reductionistic explanation lies at the heart of systems biology. In the sciences,
reductionism is mostly understood as a means to explain phenomena generated
by systems in terms of the properties of their parts, often when considered in
isolation. If complex systems that have systemic properties brought about by
the interactions of their parts are considered, where none of the parts in iso-
lation display similar properties, then reductionism is a not a fruitful strategy
