Difference of Character. The theory that this difference is innate and immutable is supported by numerous extracts from various writers of all periods, and illustrated in many ways. But all the evidence accumulated hardly amounts to more than so many hints and indications, and the matter (says Schopenhauer) was only satisfactorily explained by Kant's doctrine of the Intelligible and Empirical Character. (Cf.
The Basis of Morality · The Wunder Library — complete classics, free to read, with narration.