Chemistry Reference
In-Depth Information
knowing that this is only the tip of the iceberg. Moreover, while our theoretical
understanding might grasp chemical reactions within mixtures of ten or twenty
substances under certain conditions, it usually fails to provide comprehensive
explanations and predictions beyond that limit. The drawback of adjusting matter
in the laboratory to chemical concepts is that both our empirical and theoretical
concepts are very limited to understanding the natural world. Even inside the
laboratory, material samples never fully meet the conceptual ideal of purity,
because of practical limitations of purification procedures and for thermodynamic
reasons. Instead, any presumably pure substance can contain impurities at concen-
trations below the analytical limit. Matter, so to speak, resists purification at a
certain degree and thereby chemical conceptualization. Because even the smallest
impurity can have, through catalytic effects, a strong impact on chemical proper-
ties, there will always be uncertainty in any specific chemical statement.
Such uncertainties, both about natural and laboratory systems, can only be
reduced by considerations of relevance, that under this specific condition and for
that particular question this or that impurity in a given system is irrelevant. For
instance, for many research purposes the gases of the air dissolved in pure liquids do
not matter, for others they crucially impact the experiments. That most elements
come as a mixtures of isotopes is negligible in many field of chemistry, in others it
is essential. There are issues for which we may assume pure water to be simply
H
2
O, many others need to take into account its dissociation, and some even its
complex dynamic structure that makes it look like a mixture of hundreds of species.
The complexity of matter forces us to take different perspectives depending on
what we want to know. One might object that the limitations are only of practical
nature and that future chemistry will push the limits towards the “ideal science”, in
which every piece of matter can be analyzed with ultimate precision and described by
a “Theory of Everything” that takes any possible fact into account. However, apart
from the insurmountable practical issues of generating endless information, that ideal
runs into serious conceptual problems. From the point of view of ultimate precision,
every piece of matter is unique and no longer a sample of a species. If we thus
investigate one, two, or hundreds of samples, we could no longer draw general
conclusions from our studies about a certain kind of matter, because the notions of
both kinds and samples are no longer available. We would then lose the ability to
build general concepts and provide general knowledge, on which science essentially
rests. If, on the other hand, we later screen the endless information for what is relevant
from a certain point of view and build corresponding equivalence classes in order to
form general concepts and statements, we would just end up doing what science
actually does: building a variety of different approaches depending on what is taken
to be relevant. The “Theory of Everything”, and its philosophical counterpart of
radical nominalism, is therefore a useless and counter-intuitive idea in chemistry.
The two reasons for pluralism, multiple aims and epistemic limits, thus act in
concert. Chemistry (and probably any science faced with complexity issues) can
partially overcome its epistemic limits by diverging according to its different aims.
The following three sections look closer on what methodological pluralism in
chemistry means for some exemplary philosophical
issues:
laws of nature,
