# Can you buy research papers online

But this assertion of a priori evidence is some- times made with reference to the primary princi- ples of all natural philosophy the laws of motion and of equilibrium whether in solids or fluids.

Now, in the first place, I would observe, that the very notions of a body in uniform rectilinear motion, or of forces acting on it, are essentially ideas of experience, and certainly could have no application without reference to the real existence of matter and force. But such perplexity would be removed if we only put the c 3 22 INDUCTIVE PRINCIPLE. Equili- Again, it has been sometimes asserted, that the brium.

When can you buy research papers online some such principles have been adopted, we can then, and then only, by strict deductive reasoning from them, arrive at the theorem of the lever, which we find confirmed by experiment. Undoubtedly the mind can infer deductively this great law of fluids, as a necessary consequence from certain other assumptions, that is, when certain, yet more elementary properties of fluids are known, and taken as the basis of the science, but not other- wise. Abstract It is, indeed, quite conceivable that a reasoning theory may be con- can you buy research papers online being, who had never seen a fluid, might imagine ceived. Example of This is no imaginary case : it actually occurs in the undula- tory theory, the speculations pursued by so many philosophers on an imagined sethereal medium. When, however, by the aid of the eye, the pheno- Unapplied till optical mena of optics present themselves, we find a vast facts are introduced. Nevertheless, such applications of mathematics confer the highest pre- sumption, little or at all short of can you buy research papers online certainty, for generalising conclusions actually observed to be true only in one or two instances. To take, perhaps, the strongest instance which inverse square of has been adduced.

The law of force or intensity the dis- tance, varying as the inverse square of the distances, it is alleged, and doubtless with truth, is a conception of pure reason (so far as any mathematical conception is so) from abstract geometrical considerations, which 26 INDUCTIVE PRINCIPLE. But though these geometrical ideas throughout may be pure creations of the mind, yet the idea of any such emanation of actual force, however abs- tract, must have been derived from some ideas of experience, and certainly can apply to nothing in nature without reference to such sensible ideas.

Equal areas Again : to take what is almost an equally striking proved abs-. It is undeniably a pure result of reason that a me- taphysical point revolving about another metaphysical point by virtue of an impulse conspiring with a cen- tripetal force tending to that point, varying according to any law whatsoever, must describe areas propor- tional to the times. Where- ever these forces exist in nature, we reason deduc- tively to the conclusion of a description of equal areas, and we find it confirmed by observation.

Any new All truths paradoxes truth, even a mere matter of observation, is a paradox to prepos- in popular estimation, if it contradict a received pre- judice.

If, however, he set essay 123 help out with a mathematical know- ledge of the principle of the " composition of rotatory motion," and proceeded deductively, the explanation is easy, and its relation to a number of other im- portant cases readily manifest.

Yet the application of this mathematical theory requires the idea of a material body in rotation, inclined The ancients, notwithstanding all their refined plane. But it was not until Stevin reasoned, not upon any abstruse axioms, but on simple mechanical considerations, that the demon- stration was discovered. A highly instructive instance of the application Discovery of magneto- of an abstract principle to physical discovery may be electricity, found in the way in which Faraday reasoned to the discovery of magneto-electricity, which I cannot de- scribe better or more briefly than in the words of Mr.