We don't need to 'know' we just need to know it is 'possible'

an individual’s use of ever changing technology  whose workings the individual cannot in fact understand or explain, the individual agent within a disenchanted world does not need actually to possess or to command the scientific knowledge that grounds the technological powers upon which that individual nevertheless counts daily; he needs rather to know—or more precisely to believe—that such knowledge is, in principle, at all times available or at least possible.