1 Samuel M. Scheiner and Michael R. Willig, eds. 1. A General ...

substantial empirical content, it acquires theoretical flavor during its articulation. It is then that
its scope is specified (which observations qualify for inclusion), relationships are exposed (what
is shared among these observations), and language (definitions of facts and relationships),
sometimes formal, settled. For example, in this book (Scheiner and Willig Chapter 1), the
generalization that individuals are different (i.e., share the property of being different) from each
other is clearly based on numerous observations. However, it is not a sum of observations by
any means. The generalization uses a relationship between two individuals of “being different”.
Thus, a condensation of observations is produced by introducing a new concept, a concept of
(non-)similarity that does not apply to a single individual (or species) but, instead, it requires at
least two entities. This generalization implicitly defines the level of detail and dimensions of
comparison. The level of detail may even change along a sliding scale depending on the
evolutionary affinity of the individuals being compared: comparing individuals within a species
would require consideration of different variables than comparing different species within a
genus.
Species area curves summarized as S = CA z (where S is species richness, C is a constant,
A is area sampled, and z is scaling constant) or allometric relationships such as Di ∝ Mi -¾ (where
Di is density of species i and Mi is its mass) are good examples of other empirical generalizations
that commonly function in ecology (Gould 1979, Whittaker 1998), in spite of doubts as to their
validity (e.g., Scheiner 2004). One characteristic indicator of generalization is the (initial)
absence of theory that is capable of reproducing the underlying pattern without exceptions.
Usually, an empirical generalization provides a strong stimulus for finding a conceptual
framework that is capable of providing an explanation for the empirical pattern detected. This
was certainly the case with S=CA z for which Preston (1962) developed statistical explanation
and the equilibrium theory of island biogeography provided a additional biological mechanisms.
Also, currently, the metabolic theory of ecology (Brown et al. 2004) proposes answers for the
observation that Di ∝ Mi -¾ .
Idealizations on the other hand are theoretical devices created to explore consequences of
a feature or a relationship of interest as if no other interfering factors were at play. To continue
with an earlier example, one could assume that species are randomly distributed in
homogeneously diverse space (space in which a mix of features repeats itself over and over; cf.
Hutchinson 1961). Then one could derive a formula describing the relationship between
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