The sefer kaftor veferach from the early rishonim reports that early greek scholars met with neviim and chachamim, and that greek philosophy is a corrupted version of torah, namely kabalah.
So if socrates said it, he probably got it from yidden, not the other way around, even if the written date came before our written record, but as smerel pointed out, this isn’t the case.
“I thought it was well known,”
Either it’s well known in JTS circles (probably isn’t) or you’re pretending that something you saw online from an apikores is well known to make it look somehow authentic, but even in co-ed schools, no one teaches that chazals torah is from goyim.