_The Cause of certain phenomena being inferred, we are led to inquire into the Cause of this Cause, which inquiry must be conducted in the same manner as the previous one; and thus we have the Induction of Ulterior Causes._ APHORISM LXIII. _In contemplating the series of Causes which are themselves the effects of other causes, we are necessarily led to assume a Supreme Cause in the Order of Causation, as we assume a First Cause in Order of Succession._ 1. WE formerly[53\3] stated the objects of the researches of Science to be Laws of Phenomena and Causes; and showed the propriety and the necessity of not resting in the former object, but extending our {248} inquiries to the latter also. Inductions, in which phenomena are connected by relations of Space, Time, Number and Resemblance, belong to the former class; and of the Methods applicable to such Inductions we have treated already. In proceeding to Inductions governed by any ulterior Ideas, we can no longer lay down any Special Methods by which our procedure may be directed. A few general remarks are all that we shall offer. [Note 53\3: B. ii. c. vii.] The principal Maxim in such cases of Induction is the obvious one:--that we must be careful to possess and to apply, with perfect clearness and precision, the Fundamental Idea on which the Induction depends. We may illustrate this in a few cases. 2. _Induction of Substance._--The Idea of Substance[54\3] involves this axiom, that the weight of the whole compound must be equal to the weights of the separate elements, whatever changes the composition or separation of the elements may have occasioned. The application of this Maxim we may term the _Method of the Balance_. We have seen[55\3] elsewhere how the memorable revolution in Chemistry, the overthrow of Phlogiston, and the establishment of the Oxygen Theory, was produced by the application of this Method. We have seen too[56\3] that the same Idea leads us to this Maxim;--that _Imponderable Fluids_ are not to be admitted as _chemical_ elements of bodies. [Note 54\3: _Hist. Sc. Ideas_, Book vi. c. iii.] [Note 55\3: _Ibid._ b. vi. c. iv.] [Note 56\3: _Ibid._] Whether those which have been termed _Imponderable Fluids_,--the supposed fluids which produce the phenomena of Light, Heat, Electricity, Galvanism, Magnetism,--really exist or no, is a question, not merely of the _Laws_, but of the _Causes_ of Phenomena. It is, as has already been shown, a question which we cannot help discussing, but which is at present involved in great obscurity. Nor does it appear at all likely that we shall obtain a true view of the cause of Light, Heat, and Electricity, till we have discovered precise and general laws connecting optical, thermotical, and {249} electrical _phenomena_ with those chemical doctrines to which the Idea of Substance is necessarily applied.