21. The Science of the Whole must divide into two doctrines; into that of immaterial totalities--_Pneumatogeny_; and into that of material totalities--_Hylogeny_. Ontology teaches us the phenomenon of matter. The first phenomenon of this are the heavenly bodies comprehended by _Cosmogony_; these develop themselves further, and divide into the elements--_Stochiogeny_. From these elements the Earth element develops itself still further, and divides into minerals--_Mineralogy_; these minerals unite into one collective body, and this is _Geogeny_. The Whole in Singulars is the living or _Organic_, which again divides into plants and animals. Biology, therefore, divides into _Organogeny_, _Phytosophy_ and _Zoosophy_. After this division of the subject the question first of all arises, what is science, provided there is one. TRUTH. 22. Science is a series of necessarily inter-dependent and consecutive propositions, which rest upon a certain fundamental proposition. 23. Now, if anything be certain it can only be _one_ in number. If, then, there be only _one_ certainty, there can also be only _one_ science, from which all the rest must be derived. 24. The Mathematical is certain, and, by virtue of this character, it stands also alone. Mathematics is the only true science, and thus the primary science, the Mathesis, or Knowledge simply, as it was called by the ancients. The fundamental propositions of mathematics must, therefore, be fundamental propositions for all other sciences also. 25. Physio-philosophy is only a science when it is reducible to, i. e. can be placed upon an equal footing with, mathematics. Mathematics is the universal science; so also is Physio-philosophy, although it is only a part, or rather but a condition of the universe; both are one, or mutually congruent. 26. Mathematics is, however, a science of mere forms without substance. Physio-philosophy is, therefore, Mathematics endowed with substance. 27. The substance of Physio-philosophy must be of one kind with the form of Mathematics. 28. The certainty of mathematical propositions depends upon no proposition being essentially different from another. Though there may be much that is diversified or heterogeneous, there is nothing new in Mathematics. For to prove a mathematical proposition is to show (or demonstrate) that it is equivalent, i. e. of the same kind with another proposition. All mathematical propositions must, consequently, resemble a first proposition. 29. Physio-philosophy must also show that all its propositions, or that all things, resemble each other, and, finally, some first proposition or thing. 30. These natural propositions or natural things must, however, resemble also mathematical propositions, and depend, after all, upon the primary proposition of mathematics or the axiom. Now then comes the question, what is the first principle of Mathematics? PART I. MATHESIS--OF THE WHOLE. NOTHING.