Grice exploits a Griceian maxim

exploit (v.) c. 1400, espleiten, esploiten "to accomplish, achieve, fulfill," from Old French esploitier, espleiter "carry out, perform, accomplish," from esploit (see exploit (n.)). The sense of "use selfishly" first recorded 1838, from a sense development in French perhaps from use of the word with reference to mines, etc. (compare exploitation). Related: Exploited; exploiting.

exploit (n.) late 14c., "outcome of an action," from Old French esploit "a carrying out; achievement, result; gain, advantage" (12c., Modern French exploit), a very common word, used in senses of "action, deed, profit, achievement," from Latin explicitum "a thing settled, ended, or displayed," noun use of neuter of explicitus, past participle of explicare "unfold, unroll, disentangle," from ex "out" (see ex-) + plicare "to fold" (from PIE root *plek- "to plait").  Meaning "feat, achievement" is c. 1400. Sense evolution is from "unfolding" to "bringing out" to "having advantage" to "achievement." Related: Exploits.

 exploitative (adj.) "serving for or used in exploitation," 1882, from French exploitatif, from exploit (see exploit (n.)). Alternative exploitive (by 1859) appears to be a native formation from exploit + -ive.

exploitation (n.) 1803, "productive working" of something, a positive word among those who used it first, though regarded as a Gallicism, from French exploitation, noun of action from exploiter (see exploit (v.)). Bad sense developed 1830s-50s, in part from influence of French socialist writings (especially Saint Simon), also perhaps influenced by use of the word in U.S. anti-slavery writing; and exploitation was hurled in insult at activities it once had crowned as praise.  It follows from this science [conceived by Saint Simon] that the tendency of the human race is from a state of antagonism to that of an universal peaceful association -- from the dominating influence of the military spirit to that of the industriel one; from what they call l'exploitation de l'homme par l'homme to the exploitation of the globe by industry. ["Quarterly Review," April & July 1831]