It could still be objected that rhetoric is only useful for those whowant to outwit their audience and conceal their real aims, since someone who just wants to communicate the truth could be straightforward and would not need rhetorical tools. This, however, is not Aristotle's point of view: Even those who just try to establish what is just and true need the help of rhetoric when they are faced with a public audience. Aristotle tells us that it is impossible to teach such an audience, even if the speaker had the most exact knowledge of the subject. Obviously he thinks that the audience of a public speech consists of ordinary people who are not able to follow an exact proof based on the principles of a science. Further, such an audience can easily be distracted by factors that donot pertain to the subject at all; sometimes they are receptive to flattery or just try to increase their own advantage. And this situation becomes even worse if the constitution, the laws, and the rhetorical habits in a city are bad. Finally, most of the topics thatare usually discussed in public speeches do not allow of exact knowledge, but leave room for doubt; especially in such cases it is important that the speaker seems to be a credible person and that theaudience is in a sympathetic mood. For all those reasons, affecting the decisions of juries and assemblies is a matter of persuasiveness,not of knowledge. It is true that some people manage to be persuasiveeither at random or by habit, but it is rhetoric that gives us a method to discover all means of persuasion on any topic whatsoever.
Aristotle joins Plato in criticizing contemporary manuals of rhetoric. But how does he manage to distinguish his own project from the criticized manuals? The general idea seems to be this: Previous theorists of rhetoric gave most of their attention to methods outsidethe subject; they taught how to slander, how to arouse emotions in the audience, or how to distract the attention of the hearers from the subject. This style of rhetoric promotes a situation in which juries and assemblies no longer form rational judgments about the given issues, but surrender to the litigants. Aristotelian rhetoric is different in this respect: it is centered on the rhetorical kind of proof, the enthymeme (see below ), which is called the most important means of persuasion. Since people are most strongly convinced when they suppose that something has beenproven (Rhet. I.1, 1355a5f.), there is no need for the orator to confuse or distract the audience by the use of emotional appeals, etc. In Aristotle's view an orator will be even more successful when he just picks up the convincing aspects of a given issue, thereby using commonly-held opinions as premises. Since peoplehave a natural disposition for the true (Rhet. I.1, 1355a15f.) and every man has some contribution to make to the truth (Eudemian Ethics I.6, 1216b31,) there is no unbridgeable gapbetween the commonly-held opinions and what is true. This alleged affinity between the true and the persuasive justifies Aristotle's project of a rhetoric that essentially relies on the persuasiveness of pertinent argumentation; and it is just this argumentative character of Aristotelian rhetoric that explains the close affinity between rhetoric and dialectic (see above ).
Aristotle calls the enthymeme the “body of persuasion”, implying that everything else is only an addition or accident to the core of the persuasive process. The reason why the enthymeme, as the rhetorical kind of proof or demonstration, should be regarded as central to the rhetorical process of persuasion is that we are most easily persuaded when we think that something has been demonstrated. Hence, the basic idea of a rhetorical demonstration seems to be this:In order to make a target group believe that q, the orator must first select a sentence p or some sentences p1 … pn that are already accepted by the target group; secondly he has to show that q can be derived from p or p1 … pn, using p or p1 … pn as premises. Given that the target persons form their beliefs in accordance with rational standards, they will accept q as soon as they understand that q can be demonstrated on the basis of their own opinions.
Consequently, the construction of enthymemes is primarily a matter ofdeducing from accepted opinions (endoxa). Of course, it is also possible to use premises that are not commonly accepted by themselves, but can be derived from commonly accepted opinions; otherpremises are only accepted since the speaker is held to be credible; still other enthymemes are built from signs: see §. That a deduction is made from accepted opinions—as opposed to deductions from first and true sentences or principles—is the defining feature of dialectical argumentation in the Aristotelian sense. Thus, the formulation of enthymemes is a matter of dialectic, and the dialectician has the competence that is needed for the construction of enthymemes. If enthymemes are a subclass of dialectical arguments, then it is natural to expect a specific difference by which one can tell enthymemes apart from all other kinds of dialectical arguments (traditionally, commentators regarded logical incompleteness as such a difference; for some objections against the traditional view, see §). Nevertheless, this expectation is somehow misled: The enthymeme is different from other kinds of dialectical arguments, insofar as it isused in the rhetorical context of public speech (and rhetorical arguments are called ‘enthymemes’); thus, no further formal or qualitative differences are needed.
(c) We persuade by the argument itself when we demonstrate or seem todemonstrate that something is the case. For Aristotle, there are two species of arguments: inductions and deductions (Posterior Analytics I.1, 71a5ff.). Induction (epagôgê) is defined as the proceeding from particulars up to a universal (Topics I.12, 105a13ff.). A deduction (sullogismos) is an argument in which, certain things having been supposed, something different from the suppositions results of necessity through them (Topics I.1, 100a25ff.) or because of their being true (Prior Analytics I.2, 24b18–20). The inductive argument in rhetoric is the example (paradeigma); unlike other inductive arguments, it does not proceed from many particular cases to one universal case, but from one particular to a similar particular if both particulars fall under the same genus (Rhet. I.2, 1357b25ff.). The deductive argument in rhetoric is the enthymeme (see below ):
Aristotle, A Treatise on Government: "Besides, the notion of a city naturally precedes that of a family or an individual, for the whole must necessarily be prior to the parts, for if you take away the whole man, you cannot say a foot or a hand remains, unless by equivocation, as supposing a hand of stone to be made, but that would only be a dead one; but everything is understood to be this or that by its energic qualities and powers, so that when these no longer remain, neither can that be said to be the same, but something of the same name. That a city then precedes an individual is plain, for if an individual is not in himself sufficient to compose a perfect government, he is to a city as other parts are to a whole; but he that is incapable of society, or so complete in himself as not to want it, makes no part of a city, as a beast or a god."
Plato, Laws, Book III: "When these larger habitations grew up out of the lesser original ones, each of the lesser ones would survive in the larger; every family would be under the rule of the eldest, and, owing to their separation from one another, would have peculiar customs in things divine and human, which they would have received from their several parents who had them; and these customs would incline them to order, when the parents had the element of order in their nature, and to courage, when they had the element of courage. And they would naturally stamp upon their children, and upon their children's children, their own likings; and, as we are saying, they would find their way into the larger society, having already their own peculiar laws."
The analogy to dialectic has important implications for the status ofrhetoric. Plato argued in his Gorgias that rhetoric cannot be an art (technê), since it is not related to a definite subject, while real arts are defined by their specific subjects, as e.g. medicine or shoemaking are defined by their products, i.e., health and shoes. However, though dialectic has no definite subject, it is easy to see that it nevertheless rests on a method, because dialectic has to grasp the reason why some arguments are valid and others are not. Now, if rhetoric is nothing but the counterpart to dialectic in the domain of public speech, it must be grounded in an investigation of what is persuasive and what is not, and this, in turn, qualifies rhetoric as an art.
Aristotelian rhetoric as such is a neutral tool that can be used by persons of virtuous or depraved character. This capacity can be used for good or bad purposes; it can cause great benefits as well as great harms. There is no doubt that Aristotle himself regards his system of rhetoric as something useful, but the good purposes for which rhetoric is useful do not define the rhetorical capacity as such. Thus, Aristotle does not hesitate to concede on the one hand that his art of rhetoric can be misused. But on the other hand he tones down the risk of misuse by stressing several factors: Generally, it is true of all goods, except virtue, that they can be misused. Secondly, using rhetoric of the Aristotelian style, it is easier to convince of the just and good than of their opposites. Finally, the risk of misuse is compensated by the benefits that can be accomplished by rhetoric of the Aristotelian style.
Of course, Aristotle's rhetoric covers non-argumentative tools of persuasion as well. He tells the orator how to stimulate emotions andhow to make himself credible (see below ); his art of rhetoric includes considerations about delivery and style (see below ) and the parts of a speech. It is understandable that several interpreters found an insoluble tension between the argumentative means of pertinent rhetoric and non-argumentative tools that aim at what is outside the subject. It does not seem, however, that Aristotle himself saw a major conflict between these diverse tools ofpersuasion—presumably for the following reasons: (i) He leaves no doubt that the subject that is treated in a speech has the highestpriority (e.g. Rhet. III.1, 1403b18–27). Thus, it is not surprising that there are even passages that regard the non-argumentative tools as a sort of accidental contribution to the process of persuasion, which essentially proceeds in the manner of dialectic (cp. Rhet. I.1, 1354a15). (ii) There are, he says (III.1, 1404a2f.), methods that are not right, but necessary because of certain deficiencies of the audience. His point seems to be that the argumentative method becomes less effective, the worse the condition of the audience is. This again is to say that it is due to the badness of the audience when his rhetoric includes aspects that are not in line with the idea of argumentative and pertinent rhetoric. (iii) In dealing with methods of traditional rhetoric, Aristotle obviously assumes that even methods that have traditionallybeen used instead of argumentation can be refined so that they support the aim of an argumentative style of rhetoric. The prologue of a speech, for example, was traditionally used for appeals to the listener, but it can also be used to set out the issue of the speech,thus contributing to its clearness. Similarly, the epilogue has traditionally been used to arouse emotions like pity or anger; but assoon as the epilogue recalls the conclusions reached, it will make the speech more understandable.
systematical core of Aristotle's Rhetoric is the doctrine that there are three technical means of persuasion. The attribute ‘technical’ implies two characteristics: (i) Technical persuasion must rest on a method, and this, in turn, is to say that we must know the reason why some things are persuasive and some are not. Further, methodical persuasion must rest on a complete analysis of what it means to be persuasive. (ii) Technical means of persuasionmust be provided by the speaker himself, whereas preexisting facts, such as oaths, witnesses, testimonies, etc. are non-technical, since they cannot be prepared by the speaker.