Having formed this conception, Bruno supported it by metaphysical demonstration, and deduced conclusions bearing on psychology, religion, ethics.  Much of his polemic was directed against the deeply-rooted notion of a finite world derived from Aristotle.  Much was devoted to the proof of the Copernican discovery.  Orthodox theology was indirectly combated or plausibly caressed.  There are consequently many pages in his dialogues which do not interest a modern reader, seeing that we have outlived the conditions of thought that rendered them important.  In the process of his argument, he established the theory of a philosophical belief, a religion of religions, or ‘religione della mente,’ as he phrased it, prior to and comprehensive of all historical creeds.  He speculated, as probabilities, the transmigration of souls, and the interchangeability of types in living creatures.  He further postulated a concordance between the order of thought and the order of existence in the universe, and inclined to the doctrine of necessity in morals.  Bruno thus obtained per saltum a prospect over the whole domain of knowledge subsequently traversed by rationalism in metaphysics, theology and ethics.  In the course of these demonstrations and deductions he anticipated Descartes’ position of the identity of mind and being.  He supplied Spinoza with the substance of his reasoned pantheism; Leibnitz with his theory of monadism and pre-established harmony.  He laid down Hegel’s doctrine of contraries, and perceived that thought was a dialectic process.  The modern theory of evolution was enunciated by him in pretty plain terms.  He had grasped the physical law of the conservation of energy.  He solved the problem of evil by defining it to be a relative condition of imperfect development.  He denied that Paradise or a Golden Age is possible for man, or that, if possible, it can be considered higher in the moral scale than organic struggle toward completion by reconciliation of opposites through pain and labor.  He sketched in outline the comparative study of religions, which is now beginning to be recognized as the proper basis for theology.  Finally, he had a firm and vital hold upon that supreme speculation of the universe, considered no longer as the battle-ground of dual principles, or as the finite fabric of an almighty designer, but as the self-effectuation of an infinite unity, appearing to our intelligence as spirit and matter—­that speculation which in one shape or another controls the course of modern thought.[125]

[Footnote 125:  It was my intention to support the statements in this paragraph by translating the passages which seem to me to justify them; and I had gone so far as to make English versions of some twenty pages in length, when I found that this material would overweight my book.  A study of Bruno as the great precursor of modern thought in its more poetical and widely synthetic speculation must be left for a separate essay.  Here I may remark that the most faithful and pithily condensed abstract of Bruno’s philosophy is contained in Goethe’s poem Proemium zu Gott und Welt.  Yet this poem expresses Goethe’s thought, and it is doubtful whether Goethe had studied Bruno except in the work of his disciple Spinoza.]