Full Idea
Leibnizian monads clearly satisfy Kant's definition of noumena.
Gist of Idea
Leibnizian monads qualify as Kantian noumena
Source
Sebastian Gardner (Kant and the Critique of Pure Reason [1999], 06 'Noumena')
A Reaction
This needs qualifying, because Leibniz clearly specifies the main attributes of monads, where Kant is adamant that we can saying virtually nothing about noumena.
Book Reference
Gardner,Sebastian: 'Kant and the Critique of Pure Reason' [Routledge 1999], p.201
Related Idea
Idea 5568 We cannot know things in themselves, but are confined to appearances [Kant]