To recapitulate, therefore, the reasonings of this fection Every idea is copied from fome preceding impreffion or fentiment; and where we cannot find any impression, we may be certain that there is no idea. In all fingle inftances of the operation of bodies

whether the force of a body in motion be as its yelocity, or the fquare of its velocity; this difpute, I fay, needed not be decided by comparing its effects in equal or unequal times; but by a direct mensuration and comparison.

As to the frequent ufe of the words, Force, Power, Energy, r. which every where occur in common conversation, as well as in philosophy; that is no proof, that we are acquainted, in any inftance, with the connecting principle between cause and effect, or can account ultimately for the production of one thing by another. These words, as commonly used, have very loofe meanings annexed to them; and their ideas are very uncertain and confused. No animal can put external bodies in motion without the fentiment of a nifus or endeavour; and every animal has a fentiment or feeling from the stroke or blow of an external object, that is in motion. These fenfations, which are merely animal, and from which we can à priori draw no inference, we are apt to transfer to inanimate objects, and to fuppofe, that they have fome fuch feelings, whenever they transfer or receive motion. With regard to energies, which are exerted, without our annexing to them any idea of communicated motion, we confider only the conftant experienced conjunction of the events; and as we feel a cuftomary connexion between the ideas, we transfer that feeling to the objects; as nothing is more usual than to apply to external bodies every internal fenfation, which they occafion,

or

or minds, there is nothing that produces any impreffron, nor confequently can fuggeft any idea of power or neceffary connexion. But when many uniform inftances appear, and the fame object is always followed by the fame event; we then begin to entertain the notion of cause and connexion. We then feel a new fentiment or impreffion, viz. a customary connexion in the thought or imagination between one object and its ufual attendant; and this fentiment is the original of that idea which we feek for. For as this idea arifes from a number of fimilar inftances, and not from any fingle inftance; it must arise from that circumftance, in which the number of inftances differ from every individual inftance. But this customary connexion or transition of the imagination is the only circumstance, in which they differ. In every other particular they are alike. The first instance which we faw of motion, communicated by the shock of two billiard-balls (to return to this obvious inftance) is exactly fimilar to any inftance that may, at prefent, occur to us; except only, that we could not, at first, infer one event from the other; which we are enabled to do at present, after fo long a course of uniform experience. I know not, if the reader will readily apprehend this reafoning. I am afraid, that, fhould I multiply words about it, or throw it into a greater variety of lights, it would only become more obfcure and intricate. In all abstract reafonings, there is one point of view, which, if we

can happily hit, we shall go farther towards illustrating the fubject, than by all the eloquence and copious expreffion in the world. This we should endeavour to attain, and referve the flowers of rhetoric for fubjects which are more adapted to them.

SECTION

SECTION VIII.

Of LIBERTY and NECESSITY.

PART I

T might reasonably be expected, in questions, I which have been canvaffed and difputed with great eagerness fince the first origin of science and philofophy, that the meaning of all the terms, at least, should have been agreed upon among the difputants; and our enquiries, in the courfe of two thoufand years, been able to pass from words to the true and real fubject of the controverfy. For how eafy may it seem to give exact definitions of the terms employed in reafoning, and make these definitions, not the mere found of words, the object of future fcrutiny and examination? But if we confider the matter more narrowly, we shall be apt to draw a quite oppofite conclufion. From that circumstance alone, that a controversy has been long kept on foot, and remains ftill undecided, we may prefume, that there is fome ambiguity in the expreffion, and that the difputants affix different ideas

to the terms employed in the controverfy. For as the faculties of the foul are fuppofed to be naturally alike in every individual; otherwise nothing could be more fruitless than to reafon or dispute together; it were impoffible, if men affix the fame ideas to their terms, that they could fo long form different opinions of the fame fubject; especially when they communicate their views, and each party turn themselves on all fides, in fearch of arguments, which may give them the victory over their antagonists. 'Tis true; if men attempt the difcuffion of queftions, which lie entirely beyond the reach of human capacity, fuch as thofe concerning the origin of worlds, or the economy of the intellectual fyftem or region of fpirits, they may long beat the air in their fruitless contests, and never arrive at any determinate conclufion. But if the queftion regard any fubject of common life and experience; nothing, one would think, could preferve the difpute fo long undecided, but fome ambiguous expreffions, which keep the antagonifts ftill at a dif tance, and hinder them from grappling with each other.

THIS has been the cafe in the long difputed queftion concerning liberty and neceffity; and to fo remarkable a degree, that, if I be not much mistaken, we fhall find all mankind, both learned and ignorant, to have been always of the fame opinion with regard to that fubject, and that a few intelligible definitions

would