-Aristotle had written (Μεταφυσικά (Metaphysics), vol.A, 986b, 27) that Xenophanes was far inferior to Parmenides and in fact “slightly boorish”.
-Aristotle called the Cynic philosophers “uneducated”, when he wrote: “….the Antisthenians and the likewise uneducated….” (Μετά τα Φυσικά, (Meta ta fysika – Post Nature) vol.8, 3 (1043b, 24)).
-Aristotle wrote about Protagoras: “while the intellectuals are saying nothing of the sort, they give the impression that they are saying something of significance…” (Μετά τα Φυσικά, (Meta ta fysika – Post Nature) vol.10, 1 (1053b, 4)).
-Parmenides had taken a negative stance towards Heracletus from the beginning. He wrote somewhere: «...οι δε φορούνται κωφοί ομώς τυφλοί τε τεθηπότες άκριτα φύλαυτόν εστι κέλευθος» (Ap. 6, 8). (“..While they stumble about, deaf as well as blind, dazed – mobs without discretion, they, who do nothing but view the “being” and the “non-being” as though they are the same thing..”)
-Heracletus mocked Pythagoras (Ap.81): «Πυθαγόρας κοπίδων εστίν αρχηγός» («Pythagoras is the leader of charlatans».)
-Heracletus snubbed Hesiod, Pythagoras, Xenophanes and Hecataeus, saying (Ap.40): «Πολυμαθίη νόον έχειν ου διδάσκει˙ Ησίοδον γαρ αν εδίδαξε και Πυθαγόρην αύτις τε Ξενοφάνεά τε και Εκαταίον». (“Scholarship does not teach how to acquire intellect. If it did, then it would have taught Hesiod and Pythagoras, even Xenophanes and Hecataeus.”
-“When Empedokles told Xenophanes that a wise man cannot be found anywhere, he replied sarcastically : “of course he can’t – it takes a wise man to recognize a wise man” («Εμπεδοκλέους δε ειπόντος αυτώ ότι ανεύρετός εστιν ο σοφός, "εικότως," έφη: "σοφόν γαρ είναι δει τον επιγνωσάμενον τον σοφόν"» Diogenis Laertios, IX, 20).
-As for Epicurus, «the Stoic Diotimus, who was vehemently against him, defamed him in the worst possible manner, by circulating fifty vulgar epistles in the name of Epicurus. The same thing was done by someone else, who had collected loveletters attributed to Chrysippos and rumored them to be Epicurus’ letters. In another instance, the stoic philosopher Posidonius and his circle, along with Nikolaos and Sotion (…) maintained that Epicurus used to frequent hovels and read purification rites (…..) They also claimed that he was a procurer for one of his brothers (….), that he apparently presented as his own certain teachings of Democritus on atoms, and of Aristippus on pleasure; also that he was not a genuine Athenian citizen (…) Epictetus calls him vulgar-mouthed and insults him thoroughly. Even Timocrates – Metrodorus’ brother and student of Epicurus until he abandoned the School - had written in his play titled “Eufrantai” (Delighters) that Epicurus vomited twice a day, because he enjoyed relishing his meals, and that he (Timocrates) himself with great difficulty managed to escape from those nocturnal philosophical discussions (..) Diogenis Laertios, X, 3-6), while Timon, a sceptic and student of Pyrrhon, said of Epicurus: “…he is the most contemptible and most impertinent of all physicists, an insignificant little teacher of children that came over from Samos island, more ill-bred than the animals….” (Diogenis Laertios, X, 3).
-Correspondingly, Epicurus “referred to the Platonics as the ‘fawners of Dioysios’ (the tyrant of Syracuse), and Plato himself as ‘golden’, Aristotle as ‘a prodigal, who wasted away his paternal inheritance, was drafted in the army and sold medicines’; Protagoras was labelled a ‘porter’ and the ‘scribe of Democritus’ and ‘a provincial teacher’. He nicknamed Heracletus a “mazist” (attributed to his theory on mazes, ap.125), Democritus was nicknamed “Deliriocritus” (a ranter), Antidorus “Sannidorus” (dope), the Kyzikians (the astronomer and mathematician Evdoxos) he called “the enemies of Hellas”; the dialectics (of Megara, of his friend Socrates, Euclid) he called “envious of everything” and Pyrrhon as “uneducated and uncultured” (Diogenis Laertios X, 7-8). While for his teacher: “Epicurus himself says in his epistles on Nausiphanes: “those things caused him to be beside himself, to the point that he insulted me, calling me ‘professor’.” He also called him a squid, illiterate, a fraud and lecherer.” (Diogenis Laertios, X, 7-8).
-“He (Aristotle) in general was – according to Epicurus – the most harmful opponent for the saving of the lives of those who were preparing themselves –like athletes- for the arena of politics” (Philodemos Περί ρητορικής, (Peri Rhetorikis – On rhetorics) 2, 58, 10-15).
-In one of his two writings against the Epicurians, the “Ει καλώς είρηται το λάθε βιώσας”, (If it is good to live a discreet life) (ch.1 (1128bc), Plutarch stresses that “just as those who, with an unbridled and insatiable ambition, decry any glory in others as though they are their rival lovers, in order to attain it themselves without any competition”, thus Epicurus, instead of “living in obscurity”, proclaimed the ‘discreet lifestyle’ so that the rest of the world would follow his motto, while he reaped glory and stayed out of obscurity – which he should have done,, if he had followed his own motto.
-Plutarch wrote four books against the Stoic philosophers, accusing them –among other things- that the things they dogmatized on were even more absurd than what the poets of ancient Greek mythology asserted.
-Kleanthis had commented that the Peripatetic (Ambulatory) philosophers underwent something similar to that of a lyre, which emits a pleasant sound, but is never able to hear itself. (Diogenis Laertios, VII, 173).
-The Platonic philosopher Arcesilaus had said “I am not moved by flattery”, while the Stoic philosopher Cleanthis replied “I am flattering you, by saying that you say one thing and do another”. (Diogenis Laertios, VII, 171).
-Arcesilaus likened the Epicurians and non-Epicurians to men and eunuchs respectively.(Diogenis Laertios, IV, 6).
-Plato accused the Sophists. Plato not once mentioned the name of Democritus (who had acquired a fame in 5th century Athens similar to Plato’s today), because he despised him for his materialistic philosophy.
-Plato mockingly called the first of the Cynics –Antisthenes- “a belated in learning old man” (Σοφιστής, Sophistes 251b).
-Antisthenes respectively called Plato “conceited”: «Έσκωπτέ τε Πλάτωνα ως τετυφωμένον» (Diogenis Laertios, VI, 7).
-Plato had accused Aristotle for abandoning him: «Απέστη δε Πλάτωνος έτι περιόντος· ώστε φασίν εκείνον ειπείν, "Αριστοτέλης ημάς απελάκτισε καθαπερεί τα πωλάρια γεννηθέντα την μητέρα."» (He moved away while Plato was still nearby, which made them say “Aristotle pushed us away, like a new-born foal from its mother”) (Diogenis Laertios, V, 2).
-“Timon vituperated the Academics with the following words: The Academics’ insipid redundancies” (Diogenis Laertios, IV, 67).
-The philosopher Menedemus “snubbed the teachers of Plato’s and Xenocrates’ school” (Diogenis Laertios, II, 134).
-Diogenis the Cynic made fun of Plato and his philosophy. “Diogenis the Cynic called Euclid’s (not the mathematician) school ‘gall’, while Plato’s dissertation he called ‘waste’”. (Diogenis Laertios VI, 24, 26, 40, 53).
-Theopompos in his work Ηδυχάρη (Edichare) says: “There is nothing that is truly one, since even the number two is barely one, as Plato says”. (Diogenis Laertios, III, 26).
-Timon, in his play on words with Plato’s name, had said: «ως ανέπλασσε Πλάτων πεπλασμένα θαύματα ειδώς»). (just as Plato used to recreate odd banalities) (Diogenis Laertios, III, 26).
-Alexis in his work Αγκυλιώνα (Angylion) writes: “You speak of things you don’t know of. Go and run alongside Plato, and you will learn everything about soap and onions” (Diogenis Laertios, III, 27).
-Amphis in his work Δεξιδημίδη (Deximedes) writes: “O Plato, the only thing that you know is how to frown, knitting your brow modestly, like a snail.” (Diogenis Laertios, III, 28).
-Alexis in his work Παράσιτο (Parasitos) writes: “Rather than ranting alone with Plato”. He is also mocked by Anaxilas in his work Βοτρυλίων (Votrylion), Κίρκη (Circe) and Πλούσιες (Plousies). (Diogenis Laertios, III, 28).
-Loukianos derided Aristotle („the most obscene of all flatterers”) in his work Νεκρικοί διάλογοι Διογένους και Αλεξάνδρου (Dialogues of the Dead: Diogenes and Alexander), he also derided Empedocles (pompous, obtuse) in the (Dialogues of the Dead: Menippos and Aeakos), Plato („experienced in the art of flattering tyrants“), in his (Dialogues of the Dead: Menippos and Aeakos), and Socrates (sophist, pseudo-brave) in the (Dialogues of the Dead: Menippos and Cerberus).
-Julian recommended the reading of Pythagoras, of Plato, of Aristotle and the Stoic philosophers, but not the works of Pyrrhon (Sceptic philosopher) and Epicurus (Epistle to Arsakios). He also wrote a treatise against the Cynics. Albeit not a Cynic himself, he nevertheless gave advice to a Cynic on how to be a Cynic.
-The Neo-Platonic, Paganist philosopher Iamblichos who was a student of Porphyrios and who greatly influenced the thinking of Julian, in his work “Αβάμμωνος διδασκάλου προς την "Πορφυρίου προς Ανεβώ επιστολήν αποκρίσεις και των εν αυτή απορημάτων λύσεις” (Abammon the tutor’s Responses and solutions to the epistle of Porphysrios to Anebo) characterizes the Greeks immature by nature, with no esoteric world, incapable of discovering the truth by themselves; he accuses them of distorting with their fastidiousness all the things that they learnt from other peoples (Ιστορία του Ελληνικού Έθνους, History of the Hellenic Nation – published by Ekdotiki Athinon S.A., vol.6, page 513). Why would he say something like that, given that he was a Paganist?
-Philosophers did not limit themselves to insulting each other; Plato had actually attempted to burn Democritus’ books, but didn’t get too far, not because he changed his mind and abandoned the mentality of an ancient Greek Inquisitor, but because they convinced him that no matter how many books he burnt, they were already in the possession of many other people (Diogenis Laertios IX, 40: «Πλάτωνα θελήσαι συμφλέξαι τα Δημοκρίτου συγγράμματα, οπόσα εδυνήθη συναγαγείν, Αμύκλαν δε και Κλεινίαν τούς Πυθαγορικούς κωλύσαι αυτόν, ως ουδέν όφελος· παρά πολλοίς γαρ είναι ήδη τα βιβλία»). (Plato, having wished to burn the writings of Democritus, as many as he could collect, was hindered by the Pythagorians Amyclas and Kleinias, who convinced him that it would be of no use, as those writings were already possessed by many)
