First, students should be aware of the crucial distinction
between observation and inference. Observations are descriptive
statements about natural phenomena that are “directly”
accessible to the senses (or extensions of the senses)
and about which several observers can reach consensus with
relative ease. For example, objects released above ground
level tend to fall and hit the ground. By contrast, inferences
are statements about phenomena that are not “directly” accessible
to the senses. For example, objects tend to fall to the
ground because of “gravity.” The notion of gravity is inferential
in the sense that it can only be accessed and/or measured
through its manifestations or effects. Discussions
about gravitational forces being responsible are largely
inferential.