ex silentio

adverb, adjective

(of a theory, assumption, etc) based on a lack of evidence to the contrary

Word Origin

literally: from silence

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012