1805. | 
To the LEaitor ofthe Menthly Magazine. 
SIR, | 
Is the. Propefition, That any Thing af- 
erted to be Material can a&t at a Difiance, 
an Atfurdity, or Contradiction, or is it 
not £ 
ry O not accufe me of again involving 
1T) you and yourrea‘ers in a metaphy- 
fica) controverfy. 1 was not the mover-of 
the former ; and it reits with you to ftop 
this when you pleafe. 
But I wilh. to lay before the public the 
underwritten extracts from. Proieffor Ro- 
bifon’s Elements of Mechanical Philofo- 
phy,* a woik every way far beyond my 
7 
praife, and perhaps the beft vindicstioa - 
which has yet appeared of the ilbuftious 
Newton. I may be pardoned, at leat, for 
felting one controvert:ble pcint from 
an accumulation of irrefragable 
\ 
fuch 
truths, ; 
In p. 345 Dr. Robifon has faid—‘* New- 
ten was as anxious as any pexfon not to 
af-ribe imherent grayity to matter, or to 
ailert that a body tovli att on another at 
a diftance without fome mechanical ister-~ 
vention. I: is diffiiult ts know Newton's 
precife meaning by the word adicz, In 
very firidt language it is abfurd to fay 
that maticr can act at all, in contact, or 
at adiftance. But if oce,fhould affert, 
that the condition of a paiticle a cannot 
depend upon a particle 4 at.a diftence 
fiom it, hardly any psrfon wil fay that he 
makes th’s aflevtion from a cle:r percep. 
tion of the abfurdity of the contrary pro- 
politicn. Should a perfen fay, that the 
nere pre‘ence Of the particle & is a fuffi- 
cient reafon for a approaching it, it will 
be difficult to prove the afleruion to be ab- 
fard.”’ 
To this I have nothing to oppofe but a 
fhert and fimpie obfervation. Were T, 
or any ore, to contend ihat the particle 5 
aéted when it had vo exiftence, I believe 
this would be generally thought abfurd, 
Why it fhould be thought lefs cblurd to 
fuppofe ir toa&t where it has no exiitence, 
I can perceive mo reafor, except that we 
are more familiarized to one oruer cf per- 
ceptive relations than to another ; tothe 
intellectual ab#ract relation of time more 
than to that of /pace. But, to {peck 
Aritetelical'y, the one conditional cate- 
gory lecms quite as neeetfary as the other ; 
and a body may as well a&t when it is not 
asavubere itis not. “And indéed the Pro- 
¥ flor propeil. admits the analogy between 
our ideas of time aad fpace; the one as a 
* Edinburgh, 1804. 
MonTHLY Mac. No. 125. 
Mr. Leffi’s Remarks on Profeffar Robinfon. 33 
~relation of co-exiftence, the other of fuc- 
ceffion ; as Newton has diftingwifhed it. 
Action, at adiftance, can be only mo. 
ral action, whereby @ is the occafion of 
the act of 6, by encouraging that aét by 
prefence and manifefted concurrence of 
voli:ion and tender of fupport. Phyfcal, 
or proper and direét Action, can only be 
by actual prefence, or impulfe of contaét 
either of the body itfelf, its emanations, 
or intervening matter. But that gravita- 
tion is not the effedi of adiual contact be- 
tween the gravitating bodies, 1s intur ively 
evident in every initance other than that 
of the attrattion of cohefion, and may he - 
proved evenastothat. hat it is not an 
emanation, Dr. Robifon has proved ;* 
that it is not the refult of a chain of im. 
pulfe by inteivening bedies, or media, 
<vil has proved. Bodies therefore do aot 
really a&i at a diftance; and, as Dr. Ro- 
bifon fays, itis ablurd to fay, in ftrict lan- 
guage, that bodies a% at all. 
But if there be no agtion of bodies, 
there is no re action; for ene of thefe is 
relative and reciprocal, and neceflarily 
prefuppofes the cther. 
And it the mere prefenceof b be a fus- 
ficient reafon for a’s approaching it, this 
brings us to the Leibaitzian Theory; or, 
in other words, & has only ai occafonal 
relation to the phenomenon @3 and in no 
fenf2 produces it, but is merely the arbi- 
trary fign or fymbol appointed by the 
Deity to indicate that a will be produced 
according to a pre-eftablithed harmony of 
phenomena, neccflary to guide us in the 
production of effecis; or, in other words, 
to ule the corredtly poilofophic language 
of the Profeffor himfelf (page 82), “ to 
us Gtter is a meie phensmenon.” 
We know nothing but et powers ; and 
we can trace the principle aud efimate 
the force of thele only by their effidts.— 
Thus far the Profeflor will. agree with 
me; and perhaps. we fhall not differ when 
I add, that we bave no idea of power but 
as reterable to mind. wach 
I take matter, therefore, to be merely 
a phensmencn, appointed to limit the con- 
ditions and pre-indigate the refult of thofe 
practicable problems which it is permitted 
to us to folve ; or, in other words, of alk 
the fenlible effeéts which we either pro- 
duce or experience. 
If a bedy can act where it is not, then 
place a particle a, indcfinitely fmall, at a 
diftance greater than . any particular 
afhenable diftance from any particle or 
fyftem in the univerfe ; and this fclitary- 
particle aéts upon all thefe, and every par- 
* Page 686-94. 
E ticle 
