 Schopenhauer concurs that hypothesizing a thing-in-itself as the cause of our sensations amounts to a constitutive application and projection of the concept of causality beyond its legitimate scope, for according to Kant himself, the concept of causality only supplies knowledge when it is applied within the field of possible experience, and not outside of it. Schopenhauer therefore denies that our sensations have an external cause in the sense that we can know there is some epistemologically inaccessible object – the thing-in-itself – that exists independently of our sensations and is the cause of them.