Chemistry Reference
In-Depth Information
To understand the present state of the debate it is useful to start with Broad, for
whom chemistry “seems to offer the most plausible example of emergent behav-
iour” (Broad
1925
, p. 65). It is useful to do so because Hendry
s account is relying
'
on Broad
s. Broad uses an older distinction made by Mill (
1882
) between purely
mechanical behaviour and chemical behaviour. For Broad, a system is emergent if
its properties cannot be predicted from a knowledge of the properties of its
constituents taken separately or in other wholes, including knowledge of their
inter-relations. According to Broad, the only way to learn about the chemical
properties of a chemical compound is empirically, by studying samples of that
compound. If we start with knowledge of the components and the relations between
the components and we try to determine the properties of the compound, then - if
chemical compounds are truly emergent - we are bound to fail. Our failure is not
due to some mysterious chemical spirits similar to the ´lan vital in biology; for
Broad, the natural kinds that are the subject matter of chemistry are wholly
composed of the kinds that are the subject matter of physics. Nor is it necessarily
due to the lack of precise knowledge of the initial conditions or computational
power. Rather, the problem is more fundamental - the “unique and ultimate”
character of the laws of chemistry (Broad
1925
, p. 65). Such laws, which connect
the properties of chemical compounds with the properties of their components are
called by Broad trans-ordinal laws. According to Broad, our failure is due either to
(i) the existence of innumerable “latent” properties in each element, each of which
is manifested only in certain conditions, or (ii) to the lack of any general principle of
composition, such as the parallelogram law in dynamics, by which the behaviour of
any chemical compound could be deduced from its structure and from the behav-
iour of each of its elements in isolation (Broad
1925
, pp. 66-67).
McLaughlin interpreted Broad (or more generally British emergentism) as
holding the view that an emergent whole possesses force-generating properties of
a sort not possessed by any of its parts (McLaughlin
2008
, p. 41). On this view,
when particles are arranged in certain select configurations, new, unanticipated
forces arise. McLaughlin called these forces
configurational
.
7
In chemistry, con-
figurational forces are supposed to be sui generis chemical forces characterizing the
compounds, irreducible to physical forces characterizing the components. They are
supposed to be capable of downward causation - the ability to influence the basal
conditions from which they arise (i.e., the underlying dynamics). It is perhaps
natural to think that on Broad
'
s view these forces may be responsible for the failure
of compositionality and the emergent behaviour of chemicals, including chemical
affinity. McLaughlin contrasted configurational forces with resultant forces, i.e.,
non-emergent forces which are generated by other forces, not by configurations of
particles. “Emergence”, therefore, has been contrasted with “resultance”.
'
7
Although Broad does not use this term, McLaughlin (
2008
) interprets Broad in this way.
According to McLaughlin, “it is clear that he [i.e., Broad] maintains that certain structures of
chemical compounds can influence motion in fundamental ways” (McLaughlin
2008
, p. 47).
