ratiocination; its object, man and morals; its first duty, culture, not learning; its highest aim, happiness; its organ and the criterion of every truth, common sense.  He alone gains true knowledge who frees his understanding from prejudice and judges only after examining for himself; the joy of mental peace is given to no one who does not free his heart from foolish desires and vehement passions, and devote it to virtue, to “rational love.”  The positive doctrines of Thomasius have less interest than this general standpoint, which prefigured the succeeding period.  He divides practical philosophy into natural law which treats of the justum, politics which treats of the decorum, and ethics which treats of the honestum.  Justice bids us, Do not to others what you would not that others should do to you; decorum, Do to others as you would that they should do to you; and morality, Do to yourself as you would that others should do to themselves.  The first two laws relate to external, the third to internal, peace; legal duties may be enforced by compulsion, moral duties not.

[Footnote 1:  Thomasius:  Institutionum Jurisprudentiae Divinae Libri Tres, 1688; Fundamenta Juris Naturae et Gentium, 1705, both in Latin; in German, appeared in 1691-96 the Introduction and Application of Rational and Moral Philosophy.]

If Thomasius was the leader of those popular philosophers who, unconcerned about systematic continuity, discussed every question separately before the tribunal of common sense, and found in their lack of allegiance to any philosophical sect a sufficient guarantee of the unprejudicedness and impartiality of their reflections, Count Walter von Tschirnhausen (1651-1708; Medecina Mentis sive Artis Inveniendi Praecepta Generalia, 1687), a friend of Spinoza and Leibnitz, became the prototype of another group of the philosophers of the Illumination.  This group favored eclecticism of a more scientific kind, by starting from considerations of method and seeking to overcome the antithesis between rationalism and empiricism.  While fully persuaded of the validity and necessity of the mathematical method in philosophical investigations, as well as elsewhere, Tschirnhausen still holds it indispensable that the deductions, on the one hand, start from empirical facts, and, on the other, that they be confirmed by experiments.  Inner experience gives us four primal facts, of which the chief is the certainty of self-consciousness.  The second, that many things affect us agreeably and many disagreeably, is the basis of morals; the third, that some things are comprehensible to us and others not, the basis of logic; the fourth, that through the senses we passively receive impressions from without, the basis of the empirical sciences, in particular, of physics.  Consequently consciousness, will, understanding, and sensuous representation (imaginatio), together with corporeality, are our fundamental concepts.