In the Deutsches Museum, February, 1787, there is a dissertation by a very subtle and clear-headed man, the late Wizenmann, whose early death is to be lamented, in which he disputes the right to argue from a want to the objective reality of its object, and illustrates the point by the example of a man in love, who having fooled himself into an idea of beauty, which is merely a chimera of his own brain, would fain conclude that such an object really exists somewhere. I quite agree with him in this, in all cases where the want is founded on inclination, which cannot necessarily postulate the existence of its object even for the man that is affected by it, much less can it contain a demand valid for everyone, and therefore it is merely a subjective ground of the wish.--Kant Critique of Practical Reason.
I returned to the line above prompted by my re-reading of Beiser's beautiful treatment of the Pantheismusstreit in The Fate of Reason. It's very difficult not to come away from Beiser's narrative without thinking that Wizenmann's untimely death at age 28 (just under the age at which Hume published the Treatise) in 1787 caused great harm to the development of philosophy: every age needs its profound and intellectually honest skeptical voices, of course, but even those most fond of metaphysical speculation appreciate that the great age of German Idealism could have used Wizenmann as its Spinozistic-Humean Gewissen. Then again, the early death of Novalis (one of the patron saints of philosophical blogging), might have prevented an even more mystical strain from developing.