Born 28 July 1904 into a distinguished Dublin family, he was the son of barrister Arthur Francis Carew Meredith K.C., whose opinions were sought by Éamon de Valera in drafting the constitution of the Irish Republic (1919–22).
He worked in England until 1939 as a private tutor for university students, when he moved to Ireland, as he was a committed pacifist.
Meredith attended these lectures from 1947 on, and became keenly interested in the Lukasiewicz's detachment operation, for which—as he himself once phrased it—he "seemed to have some aptitude.
His old school friend from Winchester, William Empson, described him as "a small, gnomelike figure with a grin like a Cheshire cat and a pronounced Dublin accent (good for reading aloud from Joyce)".He did logic whenever time and opportunity presented themselves, and he did it on whatever materials came to hand: in a pub, his favored pint of porter within reach, he would use the inside of cigarette packs to write proofs for logical colleagues.
[1]He proved the shortest known axiomatic bases for a number of logic systems, such as this one-axiom basis for propositional calculus:[7]