As I understand it, Parmenides and Heraclitus were two pre-Socratic Greek philosophers whose views could not be farther apart. Parmenides believed that all change is illusory, and that there is just one indivisible entity which exists in reality. Heraclitus believed that change was the only thing constant in life, and that nothing maintains its existence or identity for longer than a moment. Yet it seems that they both had one belief in common.

In Plato's dialogue "Cratylus", the eponymous figure Cratylus, who was a follower of Heraclitus, claims that it's impossible to utter a falsehood:

Soc. Are you maintaining that falsehood is impossible? For if this is your meaning I should answer, that there have been plenty of liars in all ages.
Crat. Why, Socrates, how can a man say that which is not?- say something and yet say nothing? For is not falsehood saying the thing which is not?
Soc. Your argument, friend, is too subtle for a man of my age. But I should like to know whether you are one of those philosophers who think that falsehood may be spoken but not said?
Crat. Neither spoken nor said.

And in Plato's dialogue "Sophist", the Eleatic stranger, i.e. a foreigner from Elea who is a follower of Parmenides, makes mention of a Parmenidean argument that it's impossible to utter a falsehood:

Str. My dear friend, we are engaged in a very difficult speculation-there can be no doubt of that; for how a thing can appear and seem, and not be, or how a man can say a thing which is not true, has always been and still remains a very perplexing question. Can any one say or think that falsehood really exists, and avoid being caught in a contradiction? Indeed, Theaetetus, the task is a difficult one.
Theaet. Why?
Str. He who says that falsehood exists has the audacity to assert the being of not-being; for this is implied in the possibility of falsehood. But, my boy, in the days when I was a boy, the great Parmenides protested against this doctrine, and to the end of his life he continued to inculcate the same lesson-always repeating both in verse and out of verse: "Keep your mind from this way of enquiry, for never will you show that not-being is" - Such is his testimony, which is confirmed by the very expression when sifted a little.

So my question is, was it common among Ancient Greek philosophers to believe that uttering a falsehood is impossible, given that two philosophers as different as Parmenides and Heraclitus apparently both believed it? Do we know of other philosophers who believed it? Or is this just a strawman that Plato attributes to various interlocutors in his dialogues so it can be knocked down?

  • The said position seems clearly one that Parmenides held. It seems less suitable for Heraclitus though. So maybe Cratylus, even though he was in general a follower of Heraclitus, didn't receive this particular thesis from him. Commented Jul 30, 2017 at 23:02

3 Answers 3


Does it follow, because and if falsehood of belief or utterance is impossible, therefore lying is impossible ? Lying involves an intent to mislead. Suppose, what is logically possible, that all liars intend to mislead but always, by incompetence or a misunderstanding of language, tell the truth ? On this scenario falsehood might still be impossible yet there remain plenty of liars. On this basis Socrates' reply, to counter the claim that falsehood is impossible, that there are plenty of liars would prove nothing against the impossibility of falsehood.

Cratylus only says that falsehood is impossible. On my line of argument, he need not therefore say that lying is impossible.

The quotation from the 'Parmenides' equally relies strictly on the impossibility of falsehood, not on the impossibility of lying as characterised by the intent to mislead.


The Liar Paradox has rather long story, starting around 600BC, and which mentions Eubulides, Chrysippus, Aristotle and other Greek thinkers: this is an indirect proof that for them lying would have been somehow possible.In this line a further argument would be Marcia L Colish The stoic theory of verbal signification and the problem of lies and false statements from antiquity to St. Anselm (Archeologie du signe.Recueils d'etudes medievales 1982).

A rather complicated case however is Plato, but there is a magistral paper on the topic by J. Hintikka (Knowledge and its Objects in Plato. 1973) The point to note that there are ambiguities in the semantics of direct and indirect construction for many greek verbs. Peculiarities of the language created a powerful illusion that telling implies exitence much as in Meinong's view.

A lawyer and further an analytic philosopher would probably insist to distinguish 'intent' form 'content' and the 'accessibility of intent' in order to anounce an opinion about lying as different from uttering untruth. Some Greek thinkers might have been confused by language but without exception they all had first hand experience.


Aristotle's and Socrates's opinions are not representative of many Greek philosophers but their opinions carry much weight. Aristotle promoted deceit and Socrates "allowed" it under certain conditions. The following quotations of and about Aristotle and Socrates support my opinion.

"that the man who is able to speak false is false (and this, of course, is the man of knowledge and good sense)" (Aristotle. 2004. The metaphysics, 1025a-1025b)

Aristotle opposed creativities by opposing Plato's forms, which inspire to create. Aristotle wrote: "So we can do away with the business of Forms Being Established As Templates." (Aristotle. 2004. The metaphysics, 1034a)

"Used of a false thing. On the one hand, either because it has not been assembled or because it would be impossible for it to be assembled." (Aristotle, 2004. The Metaphysics, 1024b-1025a)

Socrates said: " 'And surely we must value truthfulness highly. For if we were right when we said just now that falsehood is no use to the gods and only useful to men as a kind of medicine, it's clearly a kind of medicine that should be entrusted to doctors and not to laymen. . . It will be for the rulers of our city, then, if anyone, to use falsehood in dealing with citizen or enemy for the good of the State; no one else must do so. And if any citizen lies to our rulers, we shall regard it as a still graver offence than it is for a patient to lie to his doctor, or for any athlete to lie to his trainer about his physical condition, or for a sailor to misrepresent to his captain any matter concerning the ship or crew, or the state of himself or his fellow-sailors.' " (Plato. 2007. The republic, 389a)


ARISTOTLE. 2004. The metaphysics. (London, England: Penguin)

PLATO. 2007. The republic. (London: Penguin)

From: http://www.africahead.co.za/Africahead/AccOfIdeas_files/2014PienaarMDIntequismsAccountingOfIdeasFairUse.html on 10 Sep 2017.

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .