Given any rule, however "fundamental" or "necessary" for science, there are always circumstances when it is advisable not only to ignore the rule, but to adopt its opposite. For example, there are circumstances when it is advisable to introduce, elaborate and defend ad hoc hypotheses, or hypotheses which contradict well-established and generally accepted experimental results, or hypotheses whose content is smaller than the content of the existing and empirically adequate alternative, or self-inconsistent hypotheses, and so on.

Copernicanism and other essential ingredients of modern science survived only because reason was frequently overruled in their past.

Events and developments, such as ... the Copernican Revolution, ... occurred only because some thinkers either decided not to be bound by certain "obvious" methodological rules, or because they unwittingly broke them.

Science is much closer to myth than a scientific philosophy is prepared to admit. It is one of the many forms of thought that have been developed by man, and not necessarily the best. It is conspicuous, noisy, and impudent, but it is inherently superior only for those who have already decided in favour of a certain ideology, or who have accepted it without ever having examined its advantages and its limits.

First-world science is one science among many; by claiming to be more it ceases to be an instrument of research and turns into a (political) pressure group.

Today science prevails not because of its comparative merits, but because the show has been rigged in its favour... It reigns supreme because some past successes have led to institutional measures (education; role of experts; role of power groups such as the AMA) that prevent a comeback of the rivals.

The material which a scientist actually has at his disposal, his laws, his experimental results, his mathematical techniques, his epistemological prejudices, his attitude towards the absurd consequences of the theories which he accepts, is indeterminate in many ways, ambiguous, and never fully separated from the historical background . This material is always contaminated by principles which he does not know and which, if known, would be extremely hard to test.