It is as unpardonable to confound the two as it is to confound sensations with things imaginary.
We may not, therefore, say that "things" are groups of sensations.

We may, if we please, describe them as complexes of qualities.

And we may not say that the "things" we perceive are really "inside" of us and are merely "projected outside." What can "inside" and "outside" mean?
Only this.

We recognize in our experience two distinct orders, the _objective order_, the system of phenomena which constitutes the material world, and the _subjective order_, the order of things mental, to which belong sensations and "ideas." That is "outside" which belongs to the objective order.

The word has no other meaning when used in this connection.