"Mad Dog" Bertie (from AtD) on 'excluded middles' and more

[Mark Kohut]

Bertrand Russell and Principia Mathematica
Bertrand Russell asserts a distinction between the "law of excluded middle" and the "law of contradiction". In The Problems of Philosophy, he cites three "Laws of Thought" as more or less "self evident" or "a priori" in the sense of Aristotle:

1.Law of identity: 'Whatever is, is.'
2.Law of noncontradiction: 'Nothing can both be and not be.'
3.Law of excluded middle: 'Everything must either be or not be.'
These three laws are samples of self-evident logical principles... (p. 72)