Hi, Master Shen Kai too recognise that scholars can hardly
define the term Dao De, so he gave a very simple explanation (he
even wishes that the explanation can be implemented in Moral
Educations in schools):
Li Ji (benefitting oneself) is Dao
Li Ren (beniffiting others) is De
Li Ji Li Ren wei zhi Dao De.
So Dao De is basically benefitting oneself and others, not harming
oneself and others, when combined together it is "Dao De".
If we can make be mindful that our daily Mind, Speech, Actions are
like that - then naturally we will be Righteous persons.