If you kidnap or drug someone to prevent her from casting her vote, then you are responsible for her failure to cast her vote. There is nothing she can do about it. If you hypnotize a person to get her to assassinate your enemy, then you are responsible for the assassination. She cannot be blamed (except in the special case in which she is a willing accomplice, allowing herself to be hypnotized, in order to be a more effective assassin). Kidnapping, drugging and hypnosis are all methods of subjecting someone else to your will. But does persuading a person to do something count as a further method of controlling her, or subjecting her to your will? Intuitively, we want to say it does not. If you persuade me not to vote, then you get me to do what you want, but you do so in a way that leaves me in control. Having been persuaded does not exempt me from blame, as having been kidnapped, drugged or hypnotized would do. However, this intuitive view proves surprisingly difficult to justify. What makes being persuaded different? Why isn't persuading someone to do something simply a further way of controlling what she does?

This question is raised vividly by The Encomium of Helen, a speech written in the 5^th century BC by the ancient Greek rhetoritician, Gorgias. Gorgias was a teacher of rhetoric, and in this speech he is celebrating its power, rather than warning of its dangers. The speech is a defence of the legendary Helen of Troy. In the story of the Trojan War, the cause of all the troubles was Helen's leaving her husband to sail off with her lover, the Trojan prince, Paris. For the Greeks, she was an obvious hate figure: not only an adultress, but someone whose actions provoked a disastrous war and caused the deaths of many brave men. Gorgias demonstrates the power of rhetoric by showing how it can be used even to defend Helen of Troy. He argues that, however she came to sail away with Paris, Helen was not to blame. Obviously, Helen was not responsible if Paris kidnapped her by force. Gorgias argues that she also was not responsible if her actions were fated by the gods (since no human can do otherwise than as the gods have fated); nor, he claims, was she responsible if she ran away with Paris because she was overcome by lust for him (since in that case, she was simply dragged around by her passions). But perhaps instead, she wasn't either kidnapped or overcome by passion, perhaps Paris simply persuaded her to go away with him, and she went willingly as a result of being persuaded. Gorgias argues that even in that case, she wasn't to blame. Being persuaded is, he claims, just another way of being forced. Each of these arguments raises interesting questions, but here I want to focus on this argument about persuasion. There is some reason to think that this was the argument that mattered most to Gorgias. After all, this speech is itself an attempt to demonstrate the power of rhetoric (that is, of a kind of persuasive speech). How does Gorgias argue that being persuaded is just like being forced?

He points out that words can have powerful effects on us. For example, we are emotionally affected by poetry. The effect of persuasion on the soul is, he says, just like the effect of drugs on the body:

His argument, then, is that being drugged and being persuaded are simply two different ways of being causally affected by something. Drugs affect your body, whereas persuasion affects your mind. If you act as you do because you have been drugged or persuaded, then the responsibility for how you act lies with the person who drugs you or persuades you.

Gorgias concludes that if Helen was persuaded, she was even less free than if she was violently kidnapped. If she was kidnapped, at least her thinking remained free, but persuasion controls both what someone does and how she thinks:

This is a powerful argument for a paradoxical conclusion. Most people will agree that the conclusion cannot be right: being persuaded is not just like being drugged or forced. But it is hard to say what exactly is wrong with the argument. You might object, for instance, that attempts to persuade people are not always successful. But that does not really distinguish being persuaded from being drugged. Drugs aren't always effective either. A more promising objection might be that it is always possible to resist being persuaded, whereas it is not always possible to resist the effects of drugs on your body. You can resist being persuaded by thinking critically about what is being said to you. If you can resist being persuaded, then you are responsible when you act wrongly as a result of being persuaded: you should have thought more critically about what you were being urged to do. This is a possible answer to Gorgias, but of course the answer is only as strong as the assumption on which it is based. Is it really true that everyone can resist being persuaded by thinking critically? After all, not everyone is good at thinking critically, and there are some people who are very skilled at persuading others. Ancient Greek sophists boasted about their ability to ‘make the weaker argument seem the stronger’ (as Aristotle tells us, Rhetoric, 2.24).

This worry about the power or rhetoric has important implications for democracy. It is natural to think that the value of democracy lies, at least in part, in the fact that it gives power to the mass of the people. But if being persuaded is just like being forced, then the people with real power in a democracy will be those who are skilled at persuasion: demagogues, who can use their skill to influence how people vote. This was one of Plato's criticisms of democracy. If decisions are made by popular vote, then political power will lie in the hands of those who are skilled at persuasion. The distorting effects of demagoguery is still a concern for modern democracies. In a recent book, Jason Stanley has discussed the nature of propaganda and the threat it poses to democracies [How Propaganda Works (Princeton, Princeton University Press, 2015)].

A natural response to this argument is to suggest some way to limit the power of demagogues in a democracy. One way to do this would be to limit freedom of speech, but that would introduce its own problems: freedom of speech itself seems an important democratic value, and in any case, there are dangers that demagogues will influence our decisions about what kind of speech should be forbidden. A more promising alternative would be to find some way of equipping the citizens of a democracy to resist the effects of demagoguery. For this reason, education has often been thought to have a key role in democracy. The idea is that well-educated citizens will be able to think critically about what they are told and will thus avoid being manipulated by rhetorical speeches. If being misled by persuasive speeches is like being drugged, then perhaps being educated is like being given an antidote in advance.

But this solution itself raises a further worry. It might be argued that education itself is simply another kind of persuasion. If so, then by educating the citizen, we simply transfer power to those who are in charge of education. Those who want to control a society by means of propaganda have always appreciated the need to be in charge of education. How, then, can we distinguish the kind of education that empowers the citizens so that they can make their own judgments, from the kind that simply manipulates them?

Again, this is a question that arose in ancient discussions. It arises interestingly in a commentary on Plato's Gorgias written by the philosopher Olympiodorus, in the 6^th century AD. Olympiodorus distinguishes between two kinds of persuasion. One kind of persuasion produces real understanding; this is education proper. Those who are educated in this way, though they are influenced by a teacher, nevertheless remain self-moved: they remain in charge of what they do, because they have a true understanding of the reasons for doing it. Olympiodorus contrasts this with another kind of persuasion. Those who are persuaded in this second way are not given understanding. They are not in charge of what they do, but are hoodwinked by those who persuade them. They are, Olympiodorus says, ‘moved by another’.

Olympiodorus defends this contrast by appealing to (what he took to be) a Platonic view. We each, he thought, have within ourselves a kind of tacit knowledge of all things. True education merely helps us to recollect this tacit knowledge that is already within us. That is why true learning is a matter of being self-moved. Although learning is prompted by a teacher, the knowledge we uncover was already within us anyway. By contrast, deceptive persuasion does not prompt us to make use of this knowledge that is within us. That is why when we are deceived by persuasion, we are fundamentally controlled by someone else.

This late Platonic argument also suggests an answer to our question about responsibility. If each of us tacitly has all knowledge, then, in a sense, each of us has the ability to resist the deceptive rhetoric. If so, then we are responsible for failing to make use of this ability and allowing ourselves to be deceived.

Of course, there are many objections that might be raised to this Platonic claim about tacit knowledge. How can we have tacit knowledge of all things without being aware of it? How could we possibly acquire such tacit knowledge? What explains the fact that some people are better than others at accessing it? Nevertheless, this Platonic view does, as we have seen, provide an answer to our questions about persuasion. As the ancient Greeks saw, these questions are especially pressing for anyone who wants to defend the value of democracy. If we reject the Platonic claim about tacit knowledge, then we are faced with the challenge of finding some alternative answer. We need to explain why being persuaded is not simply like being forced or drugged. We need to explain in what sense (if any) everyone has the power to resist being persuaded. And finally, we need to show how there can be a kind of education that is not simply another form of manipulation.