Moreover, we say of all these things, or objects, that they are the
=causes= of the sensations in question, and that the sensations are the
=effects= of these causes. For example, if we hear a certain sound, we
say it is caused by a carriage going along the road, or that it is the
effect, or the consequence, of a carriage passing along. If there is a
strong smell of burning, we believe it to be the effect of something on
fire, and look about anxiously for the cause of the smell. If we see a
tree, we believe that there is a thing or object, which is the cause of
that appearance in our field of view.