Full Idea
Kant turned the question 'How is metaphysics possible?' into 'How is metaphysical knowledge possible?' He thus turned metaphysics into epistemology, obliterating Aristotle's distinction between being qua being and being qua known.
Clarification
'Qua' means 'as' (Latin)
Gist of Idea
Kant turned metaphysics into epistemology, ignoring Aristotle's 'being qua being'
Source
report of Immanuel Kant (Critique of Pure Reason [1781]) by Cynthia Macdonald - Varieties of Things Ch.1
Book Reference
Macdonald,Cynthia: 'Varieties of Things' [Blackwell 2005], p.13
A Reaction
This makes Kant the number one villain in my philosophical pantheon, although the confusion of ontology and epistemology is found in Berkeley and others. Human speculations are not pointless, though they are difficult to verify.