ravi wrote:
>
> In this instance, as most others, the prefix
> "radical" is a meaningless distinction: e.g: "the radical left". The
> real worthwhile practise, as PKF notes, is quite the opposite of a
> paralysing scepticism: a generous anarchism.
Skepticism (plain vanilla), reasonable skepticism, starts out with, We know this and much much more, but do we know or not know the validity of Proposition X or Y or Z.
Radical scepticism is any scepticism that does not begin with acknowledging how much we know, and know with practical certainty.
In 1850 we _knew_ the validity of Newton's theory of gravity. Any thought in 1850 that did not accept the validity, the certain validity, of Newton's theory of gravity was a serious barrier to human thought, including the thought which eventually 'disproved' Newton's theory of gravity.
We know that contemporary astronomy gives us immense knowledge of the cosmos. We know that astrology gives us no knowledge of anything (except the willingness of so many to be gulled by nonsense).
Now you can be skeptical of the completeness of knowledge of the cosmos that astronomy offers, but if you challenge the legitimacy of astronomy as a mode of knowledge, certain knowledge until (some parts of it) are replaced by other, equally certain knowledge, then you are moving towards radical skepticism. We can't discover where current astronomy is incomplete or wrong except by accepting that curren astronomy gives us real (and for practical purposes, certain) knowledge, because it is only within that framework that the errors of current astronomy can be discovered.
And, incidentally, who is PKF?
Carrol