How to Write an Enthymeme
It’s safe to use enthymeme if (and only if!) you’re comfortable assuming that your reader will accept the hidden premise. To return to an earlier example, we can probably assume that your audience believes it’s wrong to hurt innocent people. However, if you’re in any doubt as to whether or not your audience will understand or agree with one of your premises, it’s important to state it clearly and, if necessary, make a case for it.
The more difficult trick is being aware of all the hidden premises in your argument. Most people employ enthymeme constantly in their writing, not because they have adopted it as a technique, but because they simply aren’t aware of their premises! Imagine a college ethics class in which students are tasked with writing persuasive essays: how many of those essays will contain enthymemes just like the one we saw in section 2?
To gain awareness of your own hidden premises and hidden assumptions, you can start by remembering that nothing follows logically from a single statement. There is no such thing as “A, therefore B” in logic. Instead, the basic structure of a logical syllogism always includes at least three parts: “A and B, therefore C.” If you see a place within your argument where you make a deduction from a single premise (“A, therefore B”), you’ll know you’ve got an enthymeme. Your task then will be to figure out what the hidden premise is, and decide whether or not you can assume that your reader will accept it.
When to Use Enthymeme
Since enthymeme is a feature of logical deduction, it only makes sense in the context of persuasive writing. In general, this means that enthymeme is a feature of formal essays, but it may also take place in creative nonfiction, when the goal of the piece is to persuade rather than to inform or entertain. Similarly, characters in fiction may employ enthymeme in their efforts to persuade one another.