First Part.- Preliminary report.- Preliminary Knowledge of Truth, Semblance, and Error.- I. What is truth?- II. Cause - Effect - Ground - Force.- III. Evidence - Of immediate Knowledge. Rational Knowledge - Knowledge of Nature.- IV. Truth and Illusion.- V. Existence - Being Awake - Dreams - Rapture.- VI. Combination of Ideas - Idealism.- VII. Continuation. The Idealist's Dispute with the Dualist. Truth-Drive and Approval- Drive. - Second Part.- Scientific Doctrinal Concepts of God's Existence.- VIII. Importance of the Investigation. On Basedow's Principle of the Duty to Believe.- Axiomata.- IX. The evidence of the pure and the applied doctrine of magnitudes. Comparison with the evidence for the proofs of God's existence. Different methods of those proofs.- X. Allegorical Dream. - Reason and Common Sense.- XI. Epicureanism. - Accident. - Chance. A Series of Causes and Effects, without End, without Beginning. Progression into Infinity, Forwards and Backwards. - The Timeless, without Beginning, without End and without Progression.- XII. Sufficient Reason for the Contingent in the Necessary. - The former is somewhere and sometimes, the latter is everywhere and all times. - The former is only in relation to space and time; the latter is unqualifiedly the best and most perfect. Everything that is, is best. - All God's thoughts, insofar as they have the best as their subject, attain actuality.- XIII. Spinozism. - Pantheism. - All is One and One is All. - Refutation.- XIV. Continued dispute with the pantheists. - Approximation. - Point of unison with them. - Innocuousness of the purified patheism. - Compatibility with religion and ethics insofar as they are practical.- XV. Lessing. - His Contribution to the Religion of Reason. - His Thoughts on Purified Pantheism.- XVI. Elucidation of the concepts of necessity, contingency, independence, and dependence. - Attempt at a new proof for the existence of God on the basis of the incompleteness of self-knowledge.- XVII. The a priori Grounds of Proof of the Existence of a supremely perfect, necessary, independent Being.