For with regard to nature, it is indeed experience which supplies us with the rule and is the source of truth; with regard to moral laws, however, ex… - Immanuel Kant

an intellectual concept abstracts from everything sensuous, it is not abstracted from sensuous things, and perhaps would be more correctly called abstracting than abstract. Intellectual concepts it is more cautious, therefore, to call pure ideas, and concepts given only empirically, abstract ideas.

....Happiness is not an ideal of reason but of imagination, resting solely on empirical grounds, and it is vain to expect that these should define an action by which one could attain the totality of a series of consequences which is really endless.

The schematicism by which our understanding deals with the phenomenal world ... is a skill so deeply hidden in the human soul that we shall hardly guess the secret trick that Nature here employs.