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Show Our Ideas of Subjlances. Book II. Bodies and divifible, nor yet how their parts cohere, they wanting that caufe of cohefion, which is given of the cohefion of the parrs of all other ~ies. But in truth, the preffure of any amMent Fluid, how great foever, can i~!o intelligible ca•fe of the cohefron of the Jolid partr of ,Hatter. For though fuch a preffure may hinder the av_ulfion of t":O pohfhed Superficies, one from ano.ther in a Line perrend1cular tothem, as m the Exporimentoftwo polifl1ed Marbles_: Yet 1tcan never,m the leaH, Iunder the feparation by a Motion! in a Lme parallel to thefe Su perfic1es. llccaufe the ambient fluid, havmga full hberty to fucc;cd '': <ach pomt ofSpacr, diferted by a lateral motion, refiih fuch a motion of Bodies fo JOined, no more, than it would refill the motion of that Body, were It on all fides 1 environed by that Fluid, and touched no other Body : And therefore, 1f there were no other caufe of cohefion, all parts of Bodies mufl be eafily feparable by fuch a lateral iliding motion. For if rhe preffure of the Ait!Ifr be the adequate caufe of cohefion, where-ever that caufe operates not, there can be no cohefion. And fince it cannot operate againfl fuch alateral feparation, (as has been fhewed,) therefore in every imaginary plain, interfeCling any mafs of Matt':', ~lu;re could be no more cohefion, than of two polifhed Superficies_; winch will always, notw1thflandmg any urut· ginable pl"l'ffure of a FlUid, eafily fl1de one from another : fo that, perh• ps, how clear an Idea foever we think we have of the Extcnfion ofBody, which is nothing but the cohefion of fohd parts, he that fball well confider it in his Mind, may have reafon to conclude, That 'tis iiJ eajit for him to have a clear Idea, how the Soul thi"kr, ar how Bod] iJ ex• tended. For fince Body is no farther, nor otherwife extended, than by the union and cohefion of its folid parts, we fl1all very ill comprehend the extenllon of Body, without underflanding wherein confifls the union and coheilon of irs parts ; which feems to me as incomp!"ehen!ible, as the manner of Thinking, and how it is performed. §.2.5. 1 allow, it is ufual for mofl .People to wonder, how any one fhould linda difficulty in what they think tbey every day obferve. Do 11e not fee, will they be ready to fay, the parts of Bodie.> flick firmly together? ls there any thing more common? And what doubt can thcre·!;e made of it? And the like, I fay, concerning Thinking, and volunrory Motion: Do we not every moment experiment it in our !elves; and there· fore can it be doubted 1 The matter of fact is dear, I confefs ; but whtn we would a little nearer look into it, and conllder how it is done, there, I chink, weare at alofs, both in the one, and the other; and can as little underfland how the partS of Body cohere, as bow we our felvcs perceive, or move. I would have any one intelligibly explain to me, how the partS of Gold, or Brafs, (that but now in fuGon were as lcofe from cne another, as the Particles of Water, or the Sands of an Hour-glafs,) come in a few moments to be fo united, and adhere fo firongly one to another, that the utmofl force of Mens arms cannot feparate them : A confidering Man will, I fuppofe, be bere at a lofs,to fatisfie his own, or another Man' Underflanding. §. >6. The little Bodiestl1at compofe that Fluid, we call Water, are fo extreamly I mall, that I have nevor· heard of any one, who by a Microfcope, (and yet I have heard of fome, that have magnified to IOcoo; nay, to much above tco,ooo times,) pretended to perceive their d•· flinG Bulk, Figure,or Motion: And the Particles of Water,are alfo fo pcrfeClly .loofe one from an.other, tbat the leaf! force fenflbly feparates them. Nay, if we confider the!t perpetual motion, we mufi allow them to have 1)0 Chap. XXIIL Our. Ideas of Subftances. no cohefion, one with another: and yet let but a fharp cold come, and they unite thcv confolidate, thefe little Atoms cohere, and are not, without great f~rce; feparable. He that could find the Bonds, that tie thefe heaps of Joofe little Bodies together fo firmly; he that could make kn?wn the Cement, that makes them fl1ck fo fall one to another, · would d•fcov. er a grear and yet unknown Secret: And yet when that was done, would he be far enough from making the extention of Body (which is the cohe!ion of its folid parts) intelligible, till he could fhew wherein conllfled the union, or confolidation of the parts of thofe Bonds, or of that Cement or of the leaf! Particle of Matter that exifls. Whereby it appears that ~his primary and fuppofed obvious Ql)a!ity of Body, will be found, when examined, to be as incomprehenfible, as any tlung belongmg to our Minds ; and a {olid extended Subj/a"ce , ar bard to 6~ conceJved, aJ a tbining one whatever difficulties fome would ralfe agamfl1t. §. 2 7. For to 'extend our Thoughts a lit_tle ~arther,_ that yreffurc, which is brought to explain the cohefion of Boches, IS as umntelhf~tble, as the cohefion it felf. For if Matter be contidered, as no doubt It IS, fimtc, let any one fend his Contemplation to the Extremities ofUniverfe, an~ there fee what conceivable Hoops, what Bond he can 1magme to hold thiS mafs of Matter, info clofe a preffure togethe_r; from whence Steel has. 1ts firmnefs, and the parts of a Dia~ond their hardnefs and tnddfolub•lay .. If Matter be finite, it mull have 1ts Extreams; and there mull be fometlung to hinder it from fcattering afunder. If to avmd t!us difficulty, any one will throw himfelf into the Suppofition and Abyfs of tnfimte Matter, let him confider what light he thereby brings to the cohelion of Body; and ·whether he be ever the nearer making it intelligible, by refolving it into a Suppofition, the moll abfurd and m;>fl ~ncomprehenfible of all other : So far is our Extenfion of Body, ( wh1ch · 1s notlung but the cohefion of folid parts,) from being clearer, or more diflinCl, when we would enquire into the Nature, Caufe, or Manner of It, than the Ide. ofThmk- ~ f . . J ~. ·2.8. Another It!ea we have of Body, is the power o commumcatJon o1 Notion bJ impu/fe; and of our Souls, the power of ex citing of Notion hy T!Jought. Thefe !dear, the.,one of Body, the other of our Mmds, every days experience clearly furnifhes us with : But 1~ here a gam we e~qmre how this is done, we are equally m the dark . . Fo_r 10 thecommumcatwn of Motion by impulfe, wherein as much Mouon IS loll to one Body, as IS !lot to the other; which is the ordina~1efl cafe , we can have no other conception, but of the paiTing of Motion out of one Body tnto another; which J think is as obfcure and unconceivable, as how our Mmds move or flop our Bodies by Thought ; which we every mbment find they do. The increafe of Motion by impulfe, w!uch IS obferved or believed fametimes to happen,is yet harder to be underflood .. ~~ have by dat!y ~xpen< nceclear cvience of Motion produced both by 1mpulfe, and by thought; but the manner how,hardly comes within our comprehenfion ;_we are qualJy at a Jofs in both. So that however we confider Mot!On,anc~tscommum~ cation either in Body or Spirit, the Idea whrch 6e/o"g" to Sprrrt,u at leaf} 8 , clear,aJ that, that 6dongJ to Body. And 1f \~'e confidGr the ~Cl1v~ .power of Moving, or, as 1 may call it, Motivlty, It IS much clearer m Spmt than Body: fmce two Bodies, Jllaced by one another at ref!, Will never afford us the Ide• of a power in the one ro· move the other, but by a borrowed motion : whereas the Mind, every day , aRords us !dear of an act1ve power of moving of Bodies; and therefore it is worth our. confideratton, whether active power be not the proper attribute of Spmts, and paiTive · U power 14-5 |