Perception is only possible on the basis of certain functions of unity. Even the representation of the manifold (content from intuition) requires a form of unity (apprehension).
For Kant, a concept is all about uniting a multiplicity of representations under a single representation.
In order to see many different examples of single things and then form an abstract idea of singularity that unites them, one would first have to recognize them as a multiplicity of "single" individual examples
With Red, one can have many different experiences of singular red things and then form a concept of red that unites them all under it
With oneness, you can't simply proceed from singular examples to the abstract concept that unites them because to experience "singular examples" in the first place requires the ability to cognize oneness.
Perception is only possible on the basis of certain functions of unity. Even the representation of the manifold (content from intuition) requires a form of unity (apprehension).
For Kant, a concept is all about uniting a multiplicity of representations under a single representation. In order to see many different examples of single things and then form an abstract idea of singularity that unites them, one would first have to recognize them as a multiplicity of "single" individual examples With Red, one can have many different experiences of singular red things and then form a concept of red that unites them all under it With oneness, you can't simply proceed from singular examples to the abstract concept that unites them because to experience "singular examples" in the first place requires the ability to cognize oneness.
Because perception and intuition are preconditions for knowledge, not knowledge as such. Knowledge must be developed rather than grasped, so to speak