The article argues against the commonly held 'green glasses' interpretation of Kant's "a priori", where any one's familiar experience must be seen as integrated by space and time and the categories. Such an interpretation does not answer Hume's problem, Which was whether any necessary connection could be found in experience. For the connections of familiar experience are customary and contingent. Passages from Kant are cited to show that he meant by 'objective experience', not familiar experience, but that body of scientific (...) observation which has been connected according to law. The "a priori" turns out to be what the scientist finds necessary for the possibility of such a connected experience. (shrink)