— René Descartes French philosopher, mathematician, and scientist 1596 - 1650

""Mais"" is French for ""but"" and the ""but in my opinion"" comes from the context of the original conversation. apud me omnia fiunt Mathematicè in Natura is in latin.

Sometimes the Latin version is incorrectly quoted as Omnia apud me mathematica fiunt.

Sources: Correspondence with Mersenne http://fr.wikisource.org/wiki/Page%3aDescartes_-_%C5%92uvres,_%C3%A9d._Adam_et_Tannery,_III.djvu/48 note for line 7 (1640), page 36, Die Wiener Zeit http://books.google.com/books?id=9Xh3fVZLCycC&pg=PA532&lpg=PA532&dq=%22Omnia+apud+me+mathematica+fiunt%22+original+zitat&source=bl&ots=CgQOrveRiM&sig=WFHwIK20r5vRZ66FwCaxo857LCU&hl=de&sa=X&ei=_Wf2UcHlJYbfsgaf1IHABg#v=onepage&q=%22Omnia%20apud%20me%20mathematica%20fiunt%22%20original%20zitat&f=false page 532 (2008); StackExchange Math Q/A Where did Descartes write... http://math.stackexchange.com/questions/454599/where-did-descartes-write-with-me-everything-turns-into-mathematics?noredirect=1#comment978229_454599

Original: (la) Mais apud me omnia fiunt Mathematicè in Natura