What is inductive reasoning?

Inductive reasoning uses specific and limited observations to draw general conclusions that can be applied more widely. So while deductive reasoning is more of a top-down approach — moving from a general premise to a specific case — inductive reasoning is the opposite. It uses a bottom-up approach to generate new premises, or hypotheses, based on observed patterns, according to the University of Illinois.

Inductive reasoning is also called inductive logic or inference. "In inductive inference, we go from the specific to the general," Wassertheil-Smoller told Live Science. "We make many observations, discern a pattern, make a generalization, and infer an explanation or a theory." 

In science, she added, there is a constant interplay between inductive and deductive reasoning that leads researchers steadily closer to a truth that can be verified with certainty, 

The reliability of a conclusion made with inductive logic depends on the completeness of the observations. For instance, let's say you have a bag of coins; you pull three coins from the bag, and each coin is a penny. Using inductive logic, you might then propose that all of the coins in the bag are pennies.

Even though all of the initial observations — that each coin taken from the bag was a penny — are correct, inductive reasoning does not guarantee that the conclusion will be true. The next coin you pull could be a quarter. 

Here's another example: "Penguins are birds. Penguins can't fly. Therefore, no birds can fly." The conclusion does not follow logically from the statements, because the only birds included in the sample were penguins.

Despite this inherent limitation, inductive reasoning has its place in the scientific method, and scientists use it to form hypotheses and theories. Researchers then use deductive reasoning to apply the theories to specific situations.

Related: Does everyone have an inner monologue? 

Inductive reasoning examples

Here are some examples of inductive reasoning:

Data: I see fireflies in my backyard every summer.
Hypothesis: This summer, I will probably see fireflies in my backyard.

Data: I tend to catch colds when people around me are sick.
Hypothesis: Colds are infectious.

Data: Every dog I meet is friendly.
Hypothesis: Most dogs are usually friendly.