Concept in self-consciousness

According to Kant, thinking can be conceived of as a faculty which remains the same in all its possible application. In general this faculty is to be described as a conceptual activity. Yet, to think concepts is to order some manifold in a determinate respect which is given by the sign of a concept. Thus, the thinking faculty must be capable of grasping some manifold under such a respect - it must provide a unity with respect to the manifold. The way to do it is determined by single functions that Kant calls functions or forms of thinking. Now according to Kant's conception, thinking provides - in the form of self-consciousness - the unity with respect to any manifold. This happens in ascriptions of the invariant meaning of self-consciousness (by the operator "I think") to the single elements of the manifold to be united. The meaning of self-consciousness does not have any distinct content, i.e. this empty content might be filled with a sign of any concept. In this way self-consciousness functions as the thinking as such.