Appealing To Incredulity And Exemplifying: The 2 Most Effective Mechanisms For Convincing (Almost) Anyone

Among the many arguments we could consider, two stand out: using incredulity (appealing to common sense) to build community and using examples to frame ideas.

They both rely on the undeniable power of evidence. It helps them connect with a wide audience, even if their thoroughness can be questioned. In other words: common sense and examples are usually effective, even if they aren't always precise.

Therefore, it's worth paying attention to them.

1. The argument from incredulity

It leverages obviousness, relying on immediate observations and intuitive reasoning.

Common sense doesn’t challenge the audience's initial perceptions, instead reinforcing their preconceived ideas, prejudices, and biases. They don't question what seems self-evident or waste time discussing what appears beyond doubt. If something seems ‘obvious’, it is assumed to be ‘true’; if it seems ‘normal’, it is assumed to be ‘just’; if it appears ‘natural’, it is assumed to be ‘good’.

Critical faculties are inhibited.

Immediate perceptions are often misleading. We have dedicated ourselves, century after century, to developing a rigorous scientific method, precisely because we understood that we could not rely on what seemed self-evident. Physics, medicine, history, sociology, and philosophy precisely arose from the need to deconstruct evidence. To build less intuitive, perhaps, but better-established knowledge. By listening to our common sense alone, would we still believe that the sun revolves around a flat Earth? Indeed, this is what our immediate perceptions lead us to believe!

Let’s take a few examples:

Example 1: "Most cancers are hereditary. So why deprive oneself of the pleasure of smoking and drinking alcohol?"

👉 It's not the cancer that's hereditary, but the gene that predisposes to the disease. And this gene will not necessarily express itself during a person's lifetime. The reality falls far short of these perceptions, as studies have shown that only 10% of cancers have a genetic origin. According to a major study published in The Lancet in 2022, 44.4% of cancer deaths worldwide are attributable to one risk factor: tobacco (33.9%), followed by alcohol (7.4%).

Example 2: "If we build more roads, we can solve traffic congestion because more roads mean more space for cars."

👉 On paper, it seems logical: if you increase the number of lanes and keep the number of vehicles the same, then you'll make traffic flow more smoothly and reduce traffic jams. In reality, however, history shows that the opposite is true. In Houston, USA, the Katy Freeway is a perfect example. It's a vast highway built in the 1960s with 2 x 6 lanes of traffic. Due to traffic congestion, it was expanded to 2 x 8 lanes in 2000; then again to 2 x 10 lanes in 2004; to 2 x 11 lanes in 2006 and finally to 2 x 13 lanes in 2008.   Yet the freeway continues to be congested, even though it now has 26 lanes.

Example 3: "If we evolved from monkeys, why are there still monkeys around? Evolution must be a lie!"

👉 Evolutionary biology explains that humans and modern monkeys share a common ancestor. Evolution is a branching process, not a linear one. The real question is, who was this common ancestor, this missing progenitor of chimpanzees and humans? We don't yet know.

All these examples of common sense statements are brutally contradicted by experts in the fields in question. However, as you can see, we need long and complex developments to refute them, whereas a few words are enough to formulate them. Such is the power of the common sense argument: a despairing asymmetry of means. This is what we called the "Brandolini Law": the amount of time and energy needed to refute nonsense is an order of magnitude greater than that needed to produce it.

As speakers or orators, common sense brings us back to the ethical dilemma of rhetoric.

It is up to us, and us alone, to decide if we want to use it, even if it means compromising our personal ethics. If your listener catches you using an effective but flimsy argument, you risk coming across as either ignorant or a demagogue.

And on the other hand, if the person you're talking to is trying to counter a common-sense argument, take the time to assess whether you should take the time to deconstruct it (this depends on the audience and the context) - and therefore get yourself into trouble in the eyes of the other listeners, or simply ignore it and return to your own arguments to move the debate forward.

But whether you're a speaker or a listener, how can you identify common-sense arguments as quickly as possible, when their very purpose is to extinguish our critical judgment?

Fortunately, they are easy to identify. Here are the 3 main “common sense” red flags to watch out for:

• conniving adverbs, e.g. “honestly”, “sincerely”, “we're not going to lie to each other”, “let's say things”... and all the innocuous innuendos that any position to the contrary would be immediately dishonest or insincere.

• appeals to consensus such as “everyone knows that” “no one can deny that” “everyone will agree that”... which give the appearance of unanimously accepted knowledge.

• age-old proverbs like “there’s no smoke without fire”. Behind the apparent wisdom of this saying throughout history we have examples of people being unjustly accused of things they didn't do, or being the victims of unfounded rumors.

2. The argument by example

An example gives materiality to an argument, a concrete representation.

But there are two situations to identify: exemplifying an argument vs arguing with an example.

Exemplifying an argument is the use of a particular case to illustrate a generality. An argument that in itself would be too theoretical or vague now takes on body, life and relief, and is therefore more likely to move the listener.

Arguing by an example means starting from a particular case as the basis for a generality. For this method of reasoning to be valid, it must be demonstrated that it is only an isolated case and is representative of a wider reality. So you'll need to be ready to provide figures, studies, testimonials, legal standards, traditions, precedents, etc. An example alone, devoid of any other argument, is not very rigorous, but could potentially make a better impression on people's minds.

Exemplify an argument or Arguing by an example: here again, the choice is a matter of personal ethics.

In the first situation, the question is whether you give yourself a chance to create an emotional imprint in the listener's mind, while in the second you have to expect that the listener won't be convinced by just one argument.

Then you might ask yourself: whoever comes up with the most rigorous argument wins?

The most rigorous argument makes a demonstration irrefutable, which leads to an inescapable conclusion. QED!

And yet... if we're forced to argue, it's because those who think the opposite of us often have equally rigorous arguments.Just as each individual is unique, despite sharing a certain set of common values, each person has his or her own hierarchy of values, as well as his or her own appreciation of risk. For some, freedom is a more important value than equality (or vice versa), tradition is more important than innovation (or vice versa), openness is more important than protectionism (or vice versa).

Always asking yourself about the hierarchy of your audience's personal core values is a real game changer in your rhetorical strategy.