The Collaborative International Dictionary
Incommensurableness
Incommensurable \In`com*men"su*ra*ble\, a. [Pref. in- not + commensurable: cf. F. incommensurable.] Not commensurable; having no common measure or standard of comparison; as, quantities are incommensurable when no third quantity can be found that is an aliquot part of both; the side and diagonal of a square are incommensurable with each other; the diameter and circumference of a circle are incommensurable.
They are quantities incommensurable.
--Burke.
-- In`com*men"su*ra*ble*ness, n. -- In`com*men"su*ra*bly,
adv.
Wiktionary
incommensurableness
n. (context rare English) incommensurability.