Commutativity

Commute comes from a Latin stem meaning to change. In the 1890s it began to be used by train companies to describe journeys that took you from A to B and then back again (from B to A). Commuters are people who take the journeyfrom home to work and then work to home on a daily basis.

This is (for my way of thinking as a physicist) best thought of in terms of logic gates.

. = . =

Here we have and as inputs into an AND gate. Both inputs have to high for the output to be high... it doesn't matter where each input is poitioned.

+ = + =

Here we have

and

as inputs into an OR gate. If either input is high the gate output will be high... it doesn't matter where each input is poitioned.