When I had realized this, it dawned upon me that any conception elucidated by philosophy, in this case the idea of liberty, had this peculiarity: Liberty is as yet an abstract idea. In order to become real, it must assume a concrete, special form. Political freedom as a glittering generality is a thing of no reality. Under such fantastic ideal the constitutionalists or the liberals conceal the liberty of the money bag. Under these circumstances, they are quite right in demanding German unity with Prussia as a head, or a republic with a grand duke at the top. The landed aristocracy also are right in demanding the liberty of that aristocracy. And the Communists are still more right, for they demand the liberty that will guarantee bread and butter for the mass of the people and will fully set free all the forces of production. From this experience and conclusion it follows that true liberty and the highest right are composed of individual liberties and rights, that are opposed to one another without being inconceivable. It is easy to proceed from this premise to the rule of thought laid down in this work, that the brain need not make any excursions into the transcendental in order to find his way through the contradictions of the real world. In this way I passed from politics to philosophy, and from philosophy to the theory of positive knowledge which I presented to the public in 1869 in my little work "The Nature of Human Brain Work." Further studies on the general powers of understanding have added to my special knowledge of this subject, so that I am now enabled to fill the old wine into a new bottle instead of publishing a new edition of my old work. The science which I present in the following pages is very limited in its circumference, but all the better founded and important in its consequences. This, I trust, will be accepted as a sufficient excuse for the recurring repetition of the same statements in a different form. My remaining confined to a single point requires no apology. What is left undone by one, is bequeathed as a problem to others. There might be some dispute over the question, how much of this positive achievement of philosophy is due to the author and to his predecessors. But that is an interminable task of small concern. No matter who hoisted the calf out of the well, so long as it is out. Anyway, this whole work treats of the concatenation and interdependence of things, and this also throws a bright light on the question of mine and thine. J. DIETZGEN. CHICAGO, March 30, 1887. THE POSITIVE OUTCOME OF PHILOSOPHY I POSITIVE KNOWLEDGE AS A SPECIAL OBJECT That which we call science nowadays was known to our ancestors by a name which then sounded very respectable and distinguished, but which has in the meantime acquired a somewhat ludicrous taste, the name of wisdom. This gradual transition of wisdom into science is a positive achievement of philosophy which well deserves our attention.