I. What is Inference?
An inference is the process of drawing a conclusion from supporting evidence. It’s when you go beyond the evidence and reach some further conclusion. We draw inferences all the time when we say things like:
- “I don’t see Anne. She said she was tired, so she must have gone home to bed.”
- “Sarah’s been at the gym a lot; she must be trying to lose weight.”
- “Jacko is a dog, and all dogs love belly rubs. So Jacko must love belly rubs.”
This sort of inference is the basic building block of all arguments.
We also make inferences when we read literature. The author gives us clues about what’s going on, and we have to figure things out based on that evidence. The author implies; the readers infer. (For the sake of simplicity, this article will focus on the inference process rather than the implication process.)
Inferences can be good or bad depending on how logical they are. The first example here is pretty good, the third is very good, and the second is actually bad. (We’ll see why in Related Terms.)
II. Examples of Inference
See below for examples of Inference.
You’re about to enter a classroom. It’s 8:57, and there is lots of chatter coming from inside the room.
–> You infer that there’s a 9:00 class that hasn’t started yet.
In this example, we have some basic evidence (the time and the noise), and we can infer that class hasn’t started yet. We can’t be sure that the inference is correct, but it’s reasonable to reach this conclusion anyway.
Socrates is a man, and all men are mortal.
–>Therefore, we can infer that Socrates is mortal.
Also known as a syllogism (see Related Terms), this is the most logically complete form of inference. Unlike Example #1, we actually can be sure this time. If the evidence is correct, then we can be quite certain that Socrates is mortal.
Harry’s face turned red and he started to yell, balling his hands up into shaking fists.
It’s not to hard to infer what Harry’s feeling here. From the evidence of his face, voice, and hands, we infer that he’s really angry about something, though we don’t yet know what it is.
III. The Importance of Inferences
Without inferences, there’s no way we could understand our world. It’s all well and good to ask for evidence and proof, but sooner or later we inevitably have to go beyond the evidence and actually draw a conclusion!
Inferences are also critically important for literature, because otherwise authors would have to explain everything to us out loud – how boring! Instead of saying “Harry turned red and started yelling,” the author would have to say “Harry felt angry.” That would be much more dry and less fun to read. So authors make their books compelling by giving you clues and rich details, then letting you draw your own conclusions as a reader. Even if the conclusions are pretty obvious (as in the example of Harry’s anger), it’s more fun as a reader if you get to make the inference for yourself.
Inferences are also the building blocks of argument, so they’re very important in formal essays. In formal essays, you want to be more clear and direct than you would be in fiction, so it’s important to state the conclusions specifically. But you also have to come in with evidence to back those conclusions up, and the relationship between evidence and conclusion is always some kind of inference. So to make a good argument, you have to make sure that the inferences are good ones! (See How to Make Good Inferences.)
IV. Examples of Inference in Literature
“I think, therefore I am.” (Rene Descartes)
This might be the most famous inference in the history of philosophy. It’s pretty sound, logically, but in fact it contains a hidden assumption (i.e. it’s an enthymeme)! The hidden assumption is: all thinking things are. So to re-write the quote as a syllogism we’d have to make it “I think, and all thinking things are. Therefore I am.”
“Whenever I find myself growing grim about the mouth; whenever it is a damp, drizzly November in my soul; whenever I find myself involuntarily pausing before coffin warehouses, and bringing up the rear of every funeral I meet…then, I account it high time to get to sea as soon as I can.” (Moby-Dick)
This quote comes from the very beginning of Moby-Dick. In it, the narrator describes his reasons for going out on the sea voyage that will bring him in contact with Ahab and the infamous Whale. From the words of this passage, we can infer a couple of things: one, that the narrator has a tendency to get depressed and “grim about the mouth”; and two, that for whatever reason he finds it helpful to be on the water.
V. Examples of Inference in Popular Culture
“Dad? Dad, come on. You gotta get up.” (The Lion King)
You probably remember this scene in The Lion King. In it, Simba finds his father, Mufasa, trampled to death by wildebeests. As viewers, we see Simba trying to wake his father up, and we infer that Simba doesn’t understand death, or can’t bring himself to believe that his father is gone. At the same time, we’re watching Simba make the wrong inference – on the basis of the evidence (his father lying motionless on the ground), he’s reached the conclusion that Mufasa is simply sleeping or knocked out.
The pilot episode of Firefly gives us a great example of audience inferences being used as red herrings. Throughout the episode, there are constant hints that Simon Tam is a federal agent sent to keep an eye on Captain Reynolds and his crew. We know, for example, that he has a large, mysterious container in the hold and that he’s very secretive about its contents. From this information, we infer that he’s the agent. But it turns out that Simon isn’t the agent, and our inferences were based on incorrect assumptions about his motives.
VI. Related Terms
People sometimes confuse the words “infer” and “assume.” But assuming is what you do when you don’t have any evidence – it’s a belief you’ve already come to ahead of time. Assumptions are related to inferences because a general assumption helps us draw conclusions in any specific case. For example, look again at the first example in §1 (the one about Anne going home). To make this inference, we have to assume that Anne was being honest about how she felt, and also that there were no other factors causing her to leave. These assumptions could be wrong! Anne might have been lying, or she might have simply stepped outside to take a phone call. However, the assumptions are reasonable and the inference is pretty convincing even though it isn’t logically complete (see Syllogism below).
Assumptions can often lead us to make bad inferences, especially if we aren’t aware of them. In the second example from section 1, we inferred that Sarah was trying to lose weight because she’s been at the gym a lot. But people visit the gym for all sorts of reasons unrelated to weight loss – they may be strength training, taking a yoga class (or teaching one), or even bodybuilding. We simply assumed that Sarah was interested in losing weight, which is not a convincing or reasonable assumption based on the evidence.
A syllogism is a logically complete statement that contains an inference. It’s logically complete because it doesn’t leave out any evidence or make any assumptions. It works entirely on the basis of stated evidence. Take, for example, the third inference from section 1, the one about Jacko the dog. This is a logically complete statement, because the conclusion (Jacko loves belly rubs) is forced on us by the evidence. In this case, the evidence might be debatable (Are there some dogs that dislike belly rubs? Is Jacko actually a coyote?) but if the evidence is true then the conclusion must be true. That’s what makes it logically complete.
This is a fancy word for a partial syllogism, one in which some evidence is assumed rather than stated. We’ve already looked at the syllogism of Jacko the dog. To make it into an enthymeme, simply drop one piece of evidence and turn it into an assumption:
- “Jacko is a dog. Therefore Jacko loves belly rubs.”
- We’re assuming that all dogs love belly rubs.
- “All dogs love belly rubs. Therefore Jacko loves belly rubs.
- We’re assuming that Jacko is a dog.
This is a literary device in which the writer sends you off on the wrong path by making you infer the wrong thing. The author predicts that you will infer a certain conclusion from the clues, but then pulls a switch and shows that this conclusion was wrong. [SPOILER ALERT:] The whole plot of The Prisoner of Azkaban is based on a series of red herrings, as we’re constantly led to believe that Snape is the evil villain when in fact it’s Peter Pettigrew