→Nineteenth Century: De Morgan, his laws, and collective/distributive distinction
==== 1854 ====
* English mathematician [[George Boole]] publishes ''The Laws of Thought'', a follow-up to his ''Mathematical Analysis of Logic'' (1847), providing a mathematical basis for [[Aristotelian logic]]. This book introduced [[boolean algebra]] as well as the concept of the "[[universe of discourse]]", although the latter may have been independently formulated by [[Augustus De Morgan]] in 1846.
==== 1879 ====