Since 1976 Hilary Putnam has drawn parallels between his `internal'',`pragmatic'', `natural'' or `common-sense'' realism and Kant''s transcendentalidealism. Putnam reads Kant as rejecting the then current metaphysicalpicture with its in-built assumptions of a unique, mind-independent world,and truth understood as correspondence between the mind and that ready-madeworld. Putnam reads Kant as overcoming the false dichotomies inherent inthat picture and even finds some glimmerings of conceptual relativity inKant''s proposed solution. Furthermore, Putnam reads Kant as overcoming thepernicious scientific realist distinction between primary and secondaryqualities, between things that really exist and their projections, adistinction that haunts modern philosophy. Putnam''s revitalisation of Kantis not just of historical interest, but challenges contemporary versions ofscientific realism. Furthermore, Putnam has highlighted themes which havenot received the attention they deserve in Kantian exegesis, namely, theproblematic role of primary and secondary qualities in Kant''s empiricalrealism, and the extent of Kant''s commitment to conceptual pluralism.However, I argue that Putnam''s qualified allegiance to Kant exposes him tosome of the same metaphysical problems that affected Kant, namely, thefamiliar problem of postulating an absolute reality (Ding an sich), while atthe same time disavowing the meaningfulness of so doing. In conclusion Isuggest that Putnam might consider Hegel''s attempts to solve this problem inKant as a way of furthering his own natural realism.