Radicals, Reactions, Realism - Philosophy of Chemistry - page 191

be observed (examples: air pump; particle accelerator), representative we call
instrumental techniques that transform one phenomenon into another (examples:
clock; thermometer), and constructive (or imitative ) experiments are made to
present the phenomenon in a “pure” form in order to mimic nature (examples:
lightning simulation; cloud chamber). One main conclusion Heidelberger draws
from his investigations in the history and philosophy of experiment is that the
nature of experimental attempts lies not solely in the testing of theories (like earlier
philosophies of science - verificationism and falsificationism - have suggested)
but in the making of reality .
How does our historical example fit that scheme? Obviously, Gomberg ' s early
preparative experiments have been entirely productive . There is no doubt that all
synthetical experiments in chemical research are performed to produce new stuff or
new phenomena or chemical species. However, particularly in this case, the pro-
duction of reality has a more “intrinsic” character, because the amount and influ-
ence of the instrumental experimentation is rather low. In order to perform a
chemical process it is necessary to bring the reaction partners into the same reaction
space and produce or provide favorable conditions. As to the Gomberg radical , the
really new aspects came into the world by the ingenious choice of - though already
well known - reaction path and reaction parameters by the experimenter.
We should not forget that methods applied to identify the material products, like
melting point measurements and elemental analysis, are part of the whole metho-
dology and of course belong to the representative section of experimentation.
An intriguing and inventive description of the interrelations between certain
observations and their correlates was given by Bas van Fraassen. Discussing
Heidelberger s suggestions, van Fraassen adds a (virtual) device to imitate rain-

bows to the list of constructive experiments ( 2008 , 94). In Chap. 4 “A Window on
the Invisible World (?)” he uses the rainbow phenomenon as a central example for
what he calls “public hallucinations”, which are assigned as entities that cannot be
represented as things, but are all the same not purely subjective ( 2008 , 105). From
our analysis of the radical concept referring to the Gomberg episode it becomes
clear that triphenylmethyl, like many other - even modern - radicals cannot
be represented as substances. Nevertheless they are extremely interesting and
describable in systematic, empirical ways. Hence it

'

is tempting to use van

Fraassen s label and call these radicals public hallucinations .

'

12.7 Concluding Remarks

Summing up this study of the epistemological status of chemical radicals of the
synthetic period with respect to historical development the following aspects seem
notable. To begin with the more systematic topics: Firstly, the classical
(or phenomenological or thermodynamical) approach of stuff characterization
appears not to come to terms with the chemical species radical in general. Only
few exceptions are stable enough under normal conditions and can be observed,