In all the sciences except Psychology we deal with objects and their changes, and leave out of account as far as possible the mind which observes them.
When we say that Philosophy tries to clear up the meanings of concepts we do not mean that it is simply concerned to substitute some long phrase for some familiar word.
It is clear that every immediate object of our senses both exists and is real in the primary meaning of these terms so long as we remain aware of the object.
It should now be clear why the method of Philosophy is so different from that of the natural sciences. Experiments are not made, because they would be utterly useless.