The Royal Society website says that the motto is "an expression of the determination of Fellows to withstand the domination of authority and to verify all statements by an appeal to facts determined by experiment." The phrase comes from
Horace's
Epistle (Book I, Epistle I) to his benefactor
Maecenas, where he claims not to be devoted to any particular sect but is rather an eclectic by nature. The motto was extracted from the first of two
hexameters, as indicated in bold: (Not bound to swear by the words of a master; where the storm drives me I turn in for shelter.) The
minor planet known as
11059 Nulliusinverba in the
asteroid belt is named after the expression. The phrase is also widely used and cited elsewhere. ==References==