Some beliefs may be subject to such instant, brutal and unambiguous rejection. For example: no left-coiling periwinkle has ever been found among millions of snails examined. If I happen to find one during my walk on Nobska beach tomorrow morning, a century of well nurtured negative evidence will collapse in an instant.

Science is all those things which are confirmed to such a degree that it would be unreasonable to withhold one's provisional consent.

World views are social constructions and they channel the search for facts. But facts are found and knowledge progresses, however fitfully.

Facts do not 'speak for themselves'; they are read in the light of theory.

In science, 'fact' can only mean 'confirmed to such a degree that it would be perverse to withhold provisional assent.' I suppose that apples might start to rise tomorrow, but the possibility does not merit equal time in physics classrooms.

But we all recognise the primary foible of frail humanity - our propensity for embracing hope and shunning logic, our tendency to believe what we desire rather than what we observe.

I am not, personally, a believer or a religious man in any sense of institutional commitment or practice. But I have a great respect for religion, and the subject has always fascinated me, beyond almost all others (with a few exceptions, like evolution and paleontology).