There are different versions of De Morgan's law, but the basic idea is as follows:
Suppose A, B, and C stand for propositions. If it's not the case that A is true and B is true and C is true, then it is the case that either A is false, or B is false, or C is false.
To believe in standard Orthodox Judaism, you need to believe in a whole bunch of propositions: god exists, created the world, and spoke to the Israelites on Mt. Sinai; the Talmud reflects what god told Moses; etc.
By De Morgan's law, standard Orthodox Judaism would be false if only one of those propositions were false. So it's much easier for me to be right than y'all to be right.