V is for Verisimilitude – Or: Good writers tell good lies.

Remember truthiness? That's the word Stephen Colbert used to explain what the truth feels like these days. Truthiness is truth that doesn't rely on logic or facts; it's whatever our gut tells us the truth must be.
That's not too different from verisimilitude, which is a literary concept meaning likeness to reality or truth. The most far-fetched fantasy novel can feel utterly real if it's written right-not just because it's anchored in the "real reality" we're used to, but because the author introduces just the right sort of details our brains need to create the experience of realness for us.
To a certain extent, verisimilitude (or truthiness) is always the writer's goal, even in nonfiction writing. Consider legal writing, for instance. When a case comes up for appeal, lawyers on both sides create a written version of events for the judge to consider. The best lawyers, it turns out, will never omit facts that are harmful to their side when writing for a judge. Why? Because as soon as the judge reads the other side's brief, the fact will come to the fore, and the side that is omitting facts will look manipulative. No one likes to be manipulated.
When you're writing an argumentative essay based on real situations, the key is to acknowledge all the important information, even if it runs counter to your argument, but to arrange the information so that your position feels right. Here are a few things that can help:
- Use visual detail. This might not be the sort of paper where you can use diagrams, or photos. But you can still write about how things look and feel.
- Arguing that obesity and cancer risk are related? Maybe you can't include the graphic, but you can describe how the sharply rising curve that results if you plot cancer rates against Body Mass Index.
- Arguing that climate change is real? Tell us what the sea ice looks like in Antarctica. Describe the look and sound of waves slapping against retainer walls in a film about Kiribati, an island nation being swallowed by rising oceans.
- You should never distort or minimize facts that run counter to your argument, but you don't have to sketch out the "visuals" for the counter-argument, and you can refrain from using vigorous, emotionally charged language that might attract the reader to it.
- Cite a lot. In law review articles (which are all about persuasion), authors are expected to footnote nearly every sentence, ideally using more than one source-ideally using a string of sources, the more the better. The sight of so many cites has an enormous, often unconscious persuasive effect.