an enquiry concerning human understanding-第8节

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who　is　rational　and　modest；　has　ever　pretended　to　assign　the
ultimate　cause　of　any　natural　operation；　or　to　show
distinctly　the　action　of　that　power；　which　produces　any
single　effect　in　the　universe。　It　is　confessed；　that　the
utmost　effort　of　human　reason　is　to　reduce　the　principles；
productive　of　natural　phenomena；　to　a　greater　simplicity；
and　to　resolve　the　many　particular　effects　into　a　few
general　causes；　by　means　of　reasonings　from　analogy；
experience；　and　observation。　But　as　to　the　causes　of　these
general　causes；　we　should　in　vain　attempt　their　discovery；
nor　shall　we　ever　be　able　to　satisfy　ourselves；　by　any
particular　explication　of　them。　These　ultimate　springs　and
principles　are　totally　shut　up　from　human　curiosity　and
enquiry。　Elasticity；　gravity；　cohesion　of　parts；
communication　of　motion　by　impulse；　these　are　probably　the
ultimate　causes　and　principles　which　we　shall　ever　discover
in　nature；　and　we　may　esteem　ourselves　sufficiently　happy；
if；　by　accurate　enquiry　and　reasoning；　we　can　trace　up　the
particular　phenomena　to；　or　near　to；　these　general
principles。　The　most　perfect　philosophy　of　the　natural　kind
only　staves　off　our　ignorance　a　little　longer：　As　perhaps
the　most　perfect　philosophy　of　the　moral　or　metaphysical
kind　serves　only　to　discover　larger　portions　of　it。　Thus　the
observation　of　human　blindness　and　weakness　is　the　result　of
all　philosophy；　and　meets　us　at　every　turn；　in　spite　of　our
endeavours　to　elude　or　avoid　it。

　　　　　Nor　is　geometry；　when　taken　into　the　assistance　of
natural　philosophy；　ever　able　to　remedy　this　defect；　or　lead
us　into　the　knowledge　of　ultimate　causes；　by　all　that
accuracy　of　reasoning　for　which　it　is　so　justly　celebrated。
Every　part　of　mixed　mathematics　proceeds　upon　the
supposition　that　certain　laws　are　established　by　nature　in
her　operations；　and　abstract　reasonings　are　employed；　either
to　assist　experience　in　the　discovery　of　these　laws；　or　to
determine　their　influence　in　particular　instances；　where　it
depends　upon　any　precise　degree　of　distance　and　quantity。
Thus；　it　is　a　law　of　motion；　discovered　by　experience；　that
the　moment　or　force　of　any　body　in　motion　is　in　the　compound
ratio　or　proportion　of　its　solid　contents　and　its　velocity；
and　consequently；　that　a　small　force　may　remove　the　greatest
obstacle　or　raise　the　greatest　weight；　if；　by　any
contrivance　or　machinery；　we　can　increase　the　velocity　of
that　force；　so　as　to　make　it　an　overmatch　for　its
antagonist。　Geometry　assists　us　in　the　application　of　this
law；　by　giving　us　the　just　dimensions　of　all　the　parts　and
figures　which　can　enter　into　any　species　of　machine；　but
still　the　discovery　of　the　law　itself　is　owing　merely　to
experience；　and　all　the　abstract　reasonings　in　the　world
could　never　lead　us　one　step　towards　the　knowledge　of　it。
When　we　reason　；　and　consider　merely　any　object　or
cause；　as　it　appears　to　the　mind；　independent　of　all
observation；　it　never　could　suggest　to　us　the　notion　of　any
distinct　object；　such　as　its　effect；　much　less；　show　us　the
inseparable　and　inviolable　connexion　between　them。　A　man
must　be　very　sagacious　who　could　discover　by　reasoning　that
crystal　is　the　effect　of　heat；　and　ice　of　cold；　without
being　previously　acquainted　with　the　operation　of　these
qualities。

　　　　　　　　　　　　　　　　　　　　　　　　　　*　*　*　*
　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　
　　　　　　　　　　　　　　　　　　　　　　　　　　PART　II。
　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　
　　　　　B/UT　we　have　not　yet　attained　any　tolerable
satisfaction　with　regard　to　the　question　first　proposed。
Each　solution　still　gives　rise　to　a　new　question　as
difficult　as　the　foregoing；　and　leads　us　on　to　farther
enquiries。　When　it　is　asked；　　the　proper　answer
seems　to　be；　that　they　are　founded　on　the　relation　of　cause
and　effect。　When　again　it　is　asked；　　it　may　be　replied　in　one　word；　E/XPERIENCE。　But
if　we　still　carry　on　our　sifting　humour；　and　ask；　　this
implies　a　new　question；　which　may　be　of　more　difficult
solution　and　explication。　Philosophers；　that　give　themselves
airs　of　superior　wisdom　and　sufficiency；　have　a　hard　task
when　they　encounter　persons　of　inquisitive　dispositions；　who
push　them　from　every　corner　to　which　they　retreat；　and　who
are　sure　at　last　to　bring　them　to　some　dangerous　dilemma。
The　best　expedient　to　prevent　this　confusion；　is　to　be
modest　in　our　pretensions；　and　even　to　discover　the
difficulty　ourselves　before　it　is　objected　to　us。　By　this
means；　we　may　make　a　kind　of　merit　of　our　very　ignorance。

　　　　　I　shall　content　myself；　in　this　section；　with　an　easy
task；　and　shall　pretend　only　to　give　a　negative　answer　to
the　question　here　proposed。　I　say　then；　that；　even　after　we
have　experience　of　the　operations　of　cause　and　effect；　our
conclusions　from　that　experience　are　not　founded　on
reasoning；　or　any　process　of　the　understanding。　This　answer
we　must　endeavour　both　to　explain　and　to　defend。

　　　　　It　must　certainly　be　allowed；　that　nature　has　kept　us
at　a　great　distance　from　all　her　secrets；　and　has　afforded
us　only　the　knowledge　of　a　few　superficial　qualities　of
objects；　while　she　conceals　from　us　those　powers　and
principles　on　which　the　influence　of　those　objects　entirely
depends。　Our　senses　inform　us　of　the　colour；　weight；　and
consistence　of　bread；　but　neither　sense　nor　reason　can　ever
inform　us　of　those　qualities　which　fit　it　for　the
nourishment　and　support　of　a　human　body。　Sight　or　feeling
conveys　an　idea　of　the　actual　motion　of　bodies；　but　as　to
that　wonderful　force　or　power；　which　would　carry　on　a　moving
body　for　ever　in　a　continued　change　of　place；　and　which
bodies　never　lose　but　by　communicating　it　to　others；　of　this
we　cannot　form　the　most　distant　conception。　But
notwithstanding　this　ignorance　of　natural　powers＇11＇　and
principles；　we　always　presume；　when　we　see　like　sensible
qualities；　that　they　have　like　secret　powers；　and　expect
that　effects；　similar　to　those　which　we　have　experienced；
will　follow　from　them。　If　a　body　of　like　colour　and
consistence　with　that　bread；　which　we　have　formerly　eat；　be
presented　to　us；　we　make　no　scruple　of　repeating　the
experiment；　and　foresee；　with　certainty；　like　nourishment
and　support。　Now　this　is　a　process　of　the　mind　or　thought；
of　which　I　would　willingly　know　the　foundation。　It　is
allowed　on　all　hands　that　there　is　no　known　connexion
between　the　sensible　qualities　and　the　secret　powers；　and
consequently；　that　the　mind　is　not　led　to　form　such　a
conclusion　concerning　their　constant　and　regular
conjunction；　by　any　thing　which　it　knows　of　their　nature。　As
to　past　；　it　can　be　allowed　to　give　　and
　information　of　those　precise　objects　only；　and
that　precise　period　of　time；　which　fell　under　its
cognizance：　But　why　this　experience　should　be　extended　to
future　times；　and　to　other　objects；　which　for　aught　we　know；
may　be　only　in　appearance　similar；　this　is　the　main　question
on　which　I　would　insist。　The　bread；　which　I　formerly　eat；
nourished　me；　that　is；　a　body　of　such　sensible　qualities
was；　at　that　time；　endued　with　such　secret　powers：　But　does
it　follow；　that　other　bread　must　also　nourish　me　at　another
time；　and　that　like　sensible　qualities　must　always　be
attended　with　like　secret　powers？　The　consequence　seems
nowise　necessary。　At　least；　it　must　be　acknowledged　that
there　is　here　a　consequence　drawn　by　the　mind；　that　there　is
a　certain　step　taken；　a　process　of　thought；　and　an
inference；　which　wants　to　be　explained。　These　two
propositions　are　far　from　being　the　same；　；　and　。
I　shall　allow；　if　you　please；　that　the　one　proposition　may
justly　be　inferred　from　the　other：　I　know；　in　fact；　that　it
always　is　inferred。　But　if　you　insist　that　the　inference　is
made　by　a　chain　of　reasoning；　I　desire　you　to　produce　that
reasoning。　The　connexion　between　these　propositions　is　not
intuitive。　There　is　required　a　medium；　which　may　enable　the
mind　to　draw　such　an　inference；　if　indeed　it　be　drawn　by
reasoning　and　argument。　What　that　medium　is；　I　must　confess；
passes　my　comprehension；　and　it　is　incumbent　on　those　to
produce　it；　who　assert　that　it　really　exists；　and　is　the
origin　of　all　our　conclusions　concerning　matter　of　fact。

　　　　　This　negative　argument　must　certainly；　in　process　of
time；　become　altogether　convincing；　if　many　penetrating　and
able　philosophers　shall　turn　their　enquiries　this　way　and　no
one　be　ever　able　to　discover　any　connecting　proposition　or
intermediate　step；　which　supports　the　understanding　in　this
conclusion。　But　as　the　question　is　yet　new；　every　reader　may
not　trust　so　far　to　his　own　penetration；　as　to　conclude；
because　an　argument　escapes　his　enquiry；　that　therefore　it
does　not　really　exist。　For　this　reason　it　may　be　requisite
to　venture　upon　a　more　difficult　task；　and　enumerating　all
the　branches　of　human　knowledge；　endeavour　to　show　that　none
of　them　can　a