Modern scholarship has often wondered whether Indian Buddhist idealism is primarily epistemic or metaphysical: does this idealism amount to a kind of transcendental scepticism according to which we cannot decide whether objects exist or not outside of consciousness because we can have no epistemic access whatsoever to these objects? Or is it rather ontologically committed, i.e., does it consist in denying the very existence of the external world? One could deem the question anachronistic and suspect that with such an inquiry we project onto Ancient and Medieval India a distinction that remains profoundly alien to it, were it not for a few preserved texts where Indian authors themselves distinguish between two such kinds of idealism within the Buddhist philosophical tradition. As already pointed out by Dan Arnold, this is the case in the commentary by Manorathanandin on Dharmakīrti’s Pramāṇavārttika; but the difference between two varieties of Buddhist idealism is also alluded to in Hindu sources, both Mīmāṃsaka and Śaiva. The present article offers a new analysis of Manorathanandin’s short and somewhat ambiguous distinction, and it examines in this connection some important remarks found in the works of the Śaiva nondualists Utpaladeva (c. 925–975) and Abhinavagupta (c. 975–1025). It shows that according to these authors, in fact the epistemic version of the Buddhist argument in favour of idealism is already metaphysical insofar as it necessarily involves a denial of the existence of the external world, and it attempts to assess the faithfulness of this Śaiva interpretation to its Buddhist sources.