> And I would upgrade this one: If there’s a chain of physical evidence (was argument), every link in the chain must work (including the premise) — not just most of them

From The Demon Haunted World:

"In the middle 1970s an astronomer I admire put together a modest manifesto called “Objections to Astrology” and asked me to endorse it. I struggled with his wording, and in the end found myself unable to sign—not because I thought astrology has any validity whatever, but because I felt (and still feel) that the tone of the statement was authoritarian. It criticized astrology for having origins shrouded in superstition. But this is true as well for religion, chemistry, medicine, and astronomy, to mention only four. The issue is not what faltering and rudimentary knowledge astrology came from, but what is its present validity.

...

The statement stressed that we can think of no mechanism by which astrology could work. This is certainly a relevant point but by itself it’s unconvincing. No mechanism was known for continental drift (now subsumed in plate tectonics) when it was proposed by Alfred Wegener in the first quarter of the twentieth century to explain a range of puzzling data in geology and paleontology. (Ore-bearing veins of rocks and fossils seemed to run continuously from Eastern South America to West Africa; were the two continents once touching and the Atlantic Ocean new to our planet?) The notion was roundly dismissed by all the great geophysicists, who were certain that continents were fixed, not floating on anything, and therefore unable to “drift.” Instead, the key twentieth-century idea in geophysics turns out to be plate tectonics; we now understand that continental plates do indeed float and “drift” (or better, are carried by a kind of conveyor belt driven by the great heat engine of the Earth’s interior), and all those great geophysicists were simply wrong. Objections to pseudoscience on the grounds of unavailable mechanism can be mistaken—although if the contentions violate well-established laws of physics, such objections of course carry great weight."