EXPERIMENTAL philosophy, that phi losophy which proceeds on experiments, which deduces the laws of nature, and the properties and powers of bodies, and their actions upon each other, from sen sible experiments and observations. The business of experimental philosophy is, to inquire into and to investigate the rea sons and causes of the various appear ances or phenomena of nature, and to make the truth or probability thereof ob vious and evident to the senses, by plain, undeniable, and adequate experiments, representing the several parts of the grand machinery and agency of nature.
In our inquries into nature, we are to be conducted by those rules and maxims which are found to be genuine, and con sonant to a just 'method of physical rea soning; and these rules of philosophis ing are, by the greatest master in science, Sir Isaac Newton, reckoned four, which are as follows : 1. More causes of natural things are not to be admitted, than are both true, and sufficient to explain the phenomena ; for nature does nothing in vain, hut is simple, and delights not in superfluous causes of things.
2. And, therefore, of natural effects of the same kind, the same causes are to be assigned, as far as it can be done ; as of respiration in man and beasts, of the de scent of stones in Europe and America, of light in a culinary fire and in the sun, and of the reflection of light in the earth and in the planets.
3. The qualities of natural bodies which cannot be increased or diminished, and agree to all bodies in which experiments can be made, are to be reckoned as the qualities of all bodies whatsoever : thus, because extension, divisibility, hardness, impenetrability, mobility, the vis iner tix, and gravity, are found in all bodies which fall under our cognizance or in spection, we may justly conclude they belong to all bodies whatsoever, and are therefore to be esteemed the original and universal properties of all natural bodies.
4. In experimental philosophy, propo sitions collected from the phxnomena by induction are to be deemed (notwith standing contrary hypotheses) either ex actly or very nearly true, till other pheno mena occur, by which they may be ren dered either more accurate, or liable to exception. This ought to be done, lest ar
guments of induction should be destroy ed by hypothesis.
These four rules of philosophising are premised by S;r Isaac Newton to his third book of the " Principia ;" and more parti cularly explained by him in his " Optics," where he exhibits the method of proceed ing in philosophy, the first part of which is as follows : "As in mathematics, so in natural his tory, the investigation of difficult things, by way of analysis, ought always to pre cede the method of composition. This analysis consists- in making experiments and observations, and in drawing gene ral conclusions from them by induction, (i. e. reasoning from the analogy of things by natural consequence) and admitting no objections against the conclusions but what are taken from experiments or certain truths. And although the argu ing from experiments and observation, by induction, be no demonstration of gene ral conclusions, yet it is the best way of arguing which the nature of things admits of, and may be looked on as so much the stronger, by how much the induction is more general ; and if no exception occur from phenomena, the conclusion may be pronounced generally : but if, at any time afterwards, any exception shall occur from experiments, it may then be pro nounced with such exceptions : by this way of analysis we may proceed from compounds to ingredients, and from mo tions to the causes producing them ; and, in general from effects to their causes; and from particular causes to more gene ral ones, till the argument ends in the most general : this is the method of ana lysis. And that of synthesis, or composi tion, consists in assuming causes, disco vered and established as principles, and by them explaining the phenomena pro ceeding from them, and proving the ex planations." See ACOUSTICS, AEROSTA. TI ON. ELECTRICITY, HYDROSTATICS, MAO rSETISM, MECHANICS, OPTICS, PNEUAIA•