Christopher Hitchens is generally credited with popularizing the idea that “what can be asserted without evidence can also be dismissed without evidence” in the English-speaking world, and in the freethought community in particular. He often referred to it as one of the elementary rules of logical thinking, for example, in this polemic against the woman widely known as Mother Teresa, in which he also had a go at the harm done by quack medicine and faith healing:
One of the curses of India, as of other poor countries, is the quack medicine man, who fleeces the sufferer by promises of miraculous healing. Sunday was a great day for these parasites, who saw their crummy methods endorsed by his holiness and given a more or less free ride in the international press. Forgotten were the elementary rules of logic, that extraordinary claims require extraordinary evidence and that what can be asserted without evidence can also be dismissed without evidence.
Many forget, though, that Hitchens’ Razor is derived from a Latin expression which was widely used in the 19th century, “Quod gratis asseritur, gratis negatur.” A quick search of Google Books reveals a pattern of usage going back as far as 1815, including authors writing in English, French, and Italian. The very earliest usage that I came across, though, was a German Bible scholar and theologian writing in Latin.
In 1704, Johann Georg Pritius first published Introductio in lectionem Novi Testamenti, in which he invoked the aforementioned epistemological razor against Artemon, presumably the third-century nontrinitarian theologian. What he wrote may be translated as “How can you prove it, Artemon? Because you asserted it without cause, therefore also it may be denied without cause.”
Seeing as his Introduction to the New Testament was widely reprinted, and Latin was still in use as the lingua franca of Biblical scholarship at the time, it is not implausible that Pritius was indeed the originator of the expression. In which case, we should consider renaming it Pritius’ Razor, in my view.
I suspect that this principle may go further back, though. If you can find an instance of it being expressed in reasonably parallel form, in any language, prior to the start of the 18th century, I’d be quite grateful to know about it.
[Thanks to Xian Adams and Miranda C. Hale for their help with Latin.]