Willard Van Orman Quine

40 robert j. fogelin
language. For parallel reasons, observation sentences also serve as
the ultimate checkpoints for science. Impressively, they do both of
these jobs without containing any theoretical content of their own.
How do these reflections bear upon ontology? For Quine, one
advantage claimed for the holophrastic treatment of observation sentences
is that “we can then study the acquisition and use of observation
sentences without prejudging what objects, if any, the component
words are meant to refer to. We are thus freed to speculate on
the nature of reification and its utility for scientific theory” (PTb 8).
Very roughly, the reason for this is as follows: Without internal structure,
a sentence cannot have a subject-predicate structure; without
a subject, there is no place for pronominalization (i.e., no open place
to quantify over); and without that, there is no variable to bind and
therefore no way of producing an ontological commitment. If all this
is correct, then ontological commitments do not have their source in
observation sentences but must occur someplace further down the
linguistic stream.
I think that we are now in a position to see why Quine thought
that his holophrastic account of observation sentences yields the
doctrine of ontological indeterminacy. If we assume, as Quine did,
that observation sentences are the sole source of content, and we further
assume, along with Quine, that the content of an observation
sentence is wholly nontheoretical, then we arrive at the result that
everything theoretical, including ontological commitments, is introduced
by us. It is in this way that objects become treated as posits, as
reifications, and sometimes as fictions. Ontological indeterminacy
emerges because a variety of different systems of theoretical posits
will always be possible relative to a set of observation sentences,
however large.
In a number of places, Quine draws this conclusion explicitly.
For example, in his “Reply to Stroud,” Quine invokes the notion of
reinterpreting a theory by replacing functions with truth-preserving
proxies. He then draws the following moral:
The structure of our theory of the world will remain unchanged. Even its
links to observational evidence will remain undisturbed, for the observation
sentences are conditioned holophrastically to stimulations, irrespective
of any shuffling of objective reference. Nothing detectable has happened.
Save the structure and you save all.
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