But we can do little more at present than give the barest outline of the positions that have been taken up.

Every search for truth must assume a certain position in this matter; in studying Eucken's philosophy it is of the first importance--more so perhaps than in the case of most other philosophers--to keep in mind clearly from the outset the position he implicitly assumes.
The simplest theory of knowledge is that of _Empiricism_, which holds that all knowledge must be gained through experience of the outside world, and of our mental states.

We see a blue wall, we obtain through our eyes an impression of blueness, and are able to make a statement: "This wall is blue." This, of course, is one of the simplest assertions that can be made, and consists merely in assigning a term--"blue"-- the meaning of which has already been agreed upon, to a colour that we appear to see on a wall.

The test of the truth of this assertion is a simple one--it is true if it corresponds with fact.

If the same assertion is made in regard to a red wall, then it is obviously untrue.
Our sense impressions give rise to a great variety of such expressions.
We state "the wall is blue" as a result of an impression obtained through the organs of sight; then we speak of a pungent smell, a sweet taste, a harsh sound, or a rough stone, on account of impressions received respectively through the organs of smell, taste, hearing, and touch.