What is Scientific Progress?

The strategy is to argue that once we have granted a notion of approximate truth, then certain
relevant propositions will have full truth (e.g. those of the form ‘approximately p’). Since such
propositions are fully true, they are potentially knowable should the right epistemic conditions be
met, and the objection in (O) does not apply.
We can accept with Psillos and Niiniluoto that in many cases we need a notion of approximate truth
without agreeing that there are no relevant propositions that can be characterized as fully true, as
(O) implies. If p is approximately true, then the proposition q, that p is approximately true, is itself
true, not merely close to the truth. This is legitimate, since if ‘planets travel in ellipses’ is a
scientific proposition, then so is ‘approximately, planets travel in ellipses’. Even if p is not true and
so not knowable, q (q = approximately p) might well be knowable. 6
One might have a conception of scientific theories whereby ‘approximately p’ is not a theory even
if ‘p’ is. After all it is ‘p’ that will be used in explaining and predicting, not ‘approximately p’. The
first point in response is that this is irrelevant to the defence of the cumulative knowledge account.
The latter says that scientific progress is the growth of scientific knowledge. Scientific knowledge
will (locally) grow when any scientific proposition becomes known, even if that proposition is
strictly speaking not a theory. Since not all scientific propositions are theories, our conception of
theories is irrelevant. Furthermore, it is not clear that ‘approximately p’ is not a theory and cannot
be used in explanation and prediction. I have taken ‘approximately p’ as equivalent to ‘p is
approximately true’. An objector may suggest that whereas ‘p’ is about the world, ‘p is
approximately true’ is a higher-order proposition about p, and for this reason is not a theory. Space
does not permit a full discussion of this point which will draw upon issues in the theory of truth.
Suffice to say that minimalists about truth will happily regard ‘p is approximately true’ as a
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