1.2 Scientific Induction
FIGURE 1.
For one thing, when you step out of your spacecraft, you fall directly to the ground. Then, when you let go of your
communications device, it falls to the ground as well. On Quim, nothing ever falls to the ground. For example, if you
had let go of your communications device back home, it would have just stayed in place by your upper appendage.
You notice that everything you let go of falls to the ground. Using inductive reasoning, you conclude that all objects
fall to the ground on Earth.
Then, you make the observation pictured (Figure1.5). You see round objects rising up into the sky, rather
than falling toward the ground as you expect. Clearly, your first conclusion—although based on many pieces
of evidence—is incorrect. You need to gather more evidence to come to a conclusion that explains all of your
observations.
FIGURE 1.
Evidence that not everything falls to the ground on Earth.Q:What conclusion might you draw based on the additional evidence of the balloons rising instead of falling?
A:With this and other evidence, you might conclude that objects heavier than air fall to the ground but objects
lighter than air do not.
Limits on Inductive Reasoning
Inductive reasoning can’t solve a crime or arrive at the correct scientific conclusion with 100 percent certainty. It’s
always possible that some piece of evidence remains to be found that would disprove the conclusion. That’s why
jurors in a trial are told to decide whether the defendant is guilty “without areasonabledoubt”—not without a shred
of doubt. Similarly, a scientific theory is never really proven conclusively to be true. However, it can be supported