What is Scientific Progress?

6 Conclusion
Given that the aim of belief is knowledge, it follows that changes in belief are progressive when
those changes increase or promote knowledge. In particular, there is progress in scientific belief
when scientific knowledge increases. This epistemic approach has not always been clearly
distinguished from the semantic counterpart, that progress is the augmentation of or improving
approximation to true belief. Yet it is clear not only that these are importantly different accounts,
but that they differ in their verdicts over actual and possible episodes. In a community which
encourages belief on flimsy evidence, scientific beliefs will come and go. On the semantic view of
progress an episode in which a truth is believed by accident and then abandoned will count as
progress followed by regress, whereas on the epistemic view, there will have been neither. This
means that the view of science as having shown for the bulk of its history a continuous and
monotonic progress is easier to maintain on the epistemic than on the semantic view. This supports
the contention that the thesis that science progresses (as conceived on the epistemic view) is the
appropriate slogan for scientific realists. Such an approach also avoids the problem of saying what
exactly increasing verisimilitude amounts to for a large, diverse, and growing body of beliefs, taken
all together.
If one is a sceptic, as Laudan is and Kuhn became then the epistemic conception of progress will
lead one to the conclusion that there has been no progress. Instead of accepting that conclusion
Laudan and Kuhn developed internalist views of progress related to problem- or puzzle-solving.
Apart from being motivated by poor sceptical arguments, the internalist conception of progress fails
to match our ordinary concept of progress, for the latter clearly is concerned with external
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