Rhetorical devices are powerful modes of expression that writers and speakers can utilize to craft effective and persuasive pieces. Different rhetorical devices can evoke different responses, emotions, and ideas. Rhetorical devices help the audiences of writings or speeches connect with the authors and the content of what is being communicated.
They are powerful in that they can be used both responsibly and irresponsibly. Because rhetorical devices have these persuasive effects, they can be used to enhance good content or conceal fallacious or poorly researched arguments. For this reason, it is important to maintain a good working knowledge of rhetorical devices. This way, in roles as either an author or an audience member, you can distinguish between responsible and irresponsible uses of rhetorical devices. Additionally, being able to evaluate the effectiveness or ineffectiveness of an author's use of rhetorical devices is a useful ability to have in any reader's toolbox for critiquing others' writing.
The difference between rhetorical devices and figures of speech
Rhetorical devices are different from figures of speech in that they are primarily used to influence the audience and emphasize ideas already present in what is being communicated. Figures of speech, on the other hand, alter the meaning of the content or can contain different or additional meaning than the literal interpretation of the utterance may contain.
Metaphors are an archetypal form of figures of speech. Take, for example, the metaphor "that person is a beast." This utterance would not typically be understood by a listener or reader to literally infer that the person is an animal, as "beast" refers to non-human animals. The internal logic of the statement would be compromised if we were to assume that it implies the object of the utterance is both human, as is implied by "person," and non-human, as is implied by "beast." Instead, the audience typically understands that the utterance is not meant to be interpreted literally. The statement can be understood to imply a number of things: the person is cruel, or the person is powerful, or the person is ignorant, et cetera.
Rhetorical devices, on the other hand, do not contain extra meaning or further implications. Rhetorical devices work on how the audience receives the information being presented to them. If used effectively, rhetorical devices can sway the audience towards the author's perspective. A good example of this persuasive power is one of the most basic rhetorical devices that exist: pathos.
Suppose that someone is making an argument for why people should be provided with free healthcare. Take, as an example in this argument, the statement, "The boy cried every night because he knew that his mother could no longer afford the medicine that was keeping her alive." In this instance, the rhetorical device is not altering the meaning or adding information to the utterance, like a figure of speech would.
The rhetorical device of pathos, or an appeal to the audience's emotions, is drawing the audience's attention to the emotional component of their idea and its impact on the lives of other people. There are not additional ways for the audience to interpret this statement; the statement is meant to be taken literally. It is a fact that the boy cried, and it is a fact that the boy's mother cannot afford to buy her medication. By combining these two facts in this manner, the author employs pathos in order to appeal to the audience with the hope that this will sway their opinions towards those of the author.
The fundamental rhetorical devices—Ethos, Pathos, Logos, and Kairos
While there are dozens of various rhetorical devices, we will focus in on the four fundamental uses of rhetoric. Mastering these can give any piece of communication you produce a persuasive and personal element that will engage your audience with interesting and memorable content.
Ethos
Ethos is the Greek word for "character." The rhetorical device of ethos is intended to draw the audience's attention towards the author's trustworthiness, credibility, and/or expertise. This rhetorical device typically takes one of two forms: either an appeal to credibility or an appeal to character. A rhetorical appeal to character may consist of the author referencing their good deeds or decisions that would show their high moral caliber. A rhetorical appeal to credibility may take the form of making known the author's relevant experience and knowledge.
Pathos
Pathos is the Greek word for "experience." This rhetorical device takes into account the audience's ideals and perceptions. Pathos draws attention to a disparity between what the audience expects or wants of the situation and the reality of the situation. It works to engage the empathy of the audience in an effort to show them that what the author is arguing for will bring about the world-situation that they view as ideal.
Logos
Logos is the Greek word for "word." Logos turns the audience's attention towards the logical structure of and evidence provided by the content of the communication. This rhetorical device focuses on making the internal logic of the communication valid. It may consist of statements that make sense in the context of the overall message and that utilize factual evidence to support its claims.
Kairos
Kairos is the Greek word for "opportunity." This rhetorical device takes into consideration the outside historical and situational context of how a message is presented. To utilize kairos, one must have an extensive knowledge about the audience and the attitudes they hold. Advertisements are often good examples of the use of kairos, as many of them exploit the popularity of contemporary trends in order to communicate their message.
Using rhetorical devices responsibly versus using rhetorical devices irresponsibly
The goal of using rhetorical devices is to make our writing or speech more engaging, persuasive, and memorable. A problem can arise, however, if we do not use these devices properly or responsibly. At times, it can be rather easy for an audience to see through the rhetorical device if it is not being used earnestly or if the content lying behind the rhetoric is not logically consistent. In these cases, the curtain drops, and what could have added a nice flourish to the piece ends up alienating the audience.
It is important to acknowledge and understand the moral component of using rhetorical devices. As such, we must keep in mind that there is a responsibility inherent in their use. Of course, not all irresponsible uses of rhetorical devices have malevolent origins or consequences. It is easy, also, for the use of rhetorical devices to slip into the realm of logical fallacies. This can happen intentionally or unintentionally, but either way, it is important to be able to identify this occurrence in our own and others' communications. A good example of this phenomenon is the rhetorical use of ethos.
If used correctly, it can imbue the audience with a sense of trust in the author, which can greatly help in convincing the audience of the author's aims. An expert witness testifying before a jury during a trial is a good example of this. The experience and knowledge that the expert has gained from their education and professional training make them more qualified than others to speak about certain subjects. The jury is expected to trust the expert's opinions on the grounds that they know more about the subject.
Or similarly, one may say, "My experience as a teacher has proven to me that students are more likely to achieve success when they are personally invested in their own education." In this case, the personal experience of the speaker is given as the evidence that they have a particular expertise in the subject at hand; and while their opinion is not immune to criticism, it should be considered as more likely to be accurate than a non-expert's opinion.
If used incorrectly, it can backfire and lead to the audience being less likely to be persuaded by the author. Take, for example, the classic "four out of five dentists recommend this toothpaste" advertising cliché. This may seem like a legitimate use of ethos, and under certain circumstances, it can be. However, if we evaluate the advertisement in itself, the author (the creator/s of the advertisement) is falling prey to the logical fallacy of appeal to authority, or argument from authority. This logical fallacy occurs when an argument is supported primarily by the assertion that an authority figure endorses the argument rather than basing the argument on the logical presentation of factual evidence.
In our toothpaste example, we are not given any factual evidence for why this toothpaste is better than others; we are simply told that authority figures endorse it, and so we should too. So, it is first and foremost important to have a logically formulated argument based on true evidence before we ever begin to think about incorporating rhetorical devices.