[1] The entry up to this point -- the first four words in Greek, Adler's headword phrase included -- was perhaps intended as a headword phrase, since the same four words are found, with only a slight difference in word order, at the beginning of Julian, Epistle 8 (noted by Adler): nothing is more advantageous to mankind than filosofei=n e)pi/ sxolh=s a(pragmo/nws. The source could also [WH] be a comment on Cassius Dio 61.10.5 (= Constantine Porphyrogenitus, Excerpta de virtutibus 2.348) where the phrase e)pi\ sxolh=s filosofei=n occurs.
[2] Adler cites for comparison a scholion on Plato, Euthyphro 6C (where the phrase 'at leisure' occurs, and the gloss is e)pi\ th=s para\ toi=s polloi=s legome/nhs eu)kairi/as). See sigma 1802, end.