Abstract
In the first two decades of the century Vvedenskij developed and defended what he took to be an original argument in support of the impossibility of metaphysical knowledge. This argument, which he hailed as a proof, involved an examination of the four laws of thought alone. As it made no appeal to the highly technical analyses found in Kant''s first Critique, Vvedenskij considered it to be more efficient and thereby effective than Kant''s own arguments. Although Vvedenskij''s estimation of his accomplishment actually increased with the passage of time, the proof rested on highly dubious assumptions.