96. III. The Analytico-Synthetic Method. Conclusion. -- Two scientific methods are commonly distinguished: that of the exact sciences, synthesis; that of the sciences of observation, analysis. Synthesis is indeed the basis of the first of these groups of sciences, and analysis of the second; but neither character belongs exclusively to either group.

The axioms which lie at the basis of the exact sciences inevitably rest upon certain elementary observations.

The results obtained by analysis and induction in the positive sciences prepare the material for synthetic deductions. All science, in fact, aims at the knowledge of things by their causes. The demonstration propter quid alone is rigorously scientific. Even the particular sciences, which have nature for their object (e. g., mechanics, optics, chemistry), endeavor to link their conclusions with mathematics and metaphysics.

Finally, then, the only scientific method is inductivo-deductive and analytico-synthetic.^{1}

{1} After these notions of general methodology, it would be in place, in special methodology, to determine the method proper to each science. On this subject we recommend De la méthode dans les sciences, by various professors, Paris, Alcan, 1909.