the critique of pure reason- 第46部分

it　is；　with　all　to　which　it　serves　as　condition；　a　nonentity。　But

the　foundation　for　this　kind　of　idealism　we　have　already　destroyed

in　the　transcendental　aesthetic。　Problematical　idealism；　which　makes

no　such　assertion；　but　only　alleges　our　incapacity　to　prove　the

existence　of　anything　besides　ourselves　by　means　of　immediate

experience；　is　a　theory　rational　and　evidencing　a　thorough　and

philosophical　mode　of　thinking；　for　it　observes　the　rule　not　to　form　a

decisive　judgement　before　sufficient　proof　be　shown。　The　desired　proof

must　therefore　demonstrate　that　we　have　experience　of　external　things；

and　not　mere　fancies。　For　this　purpose；　we　must　prove；　that　our

internal　and；　to　Descartes；　indubitable　experience　is　itself

possible　only　under　the　previous　assumption　of　external　experience。



　　　　　　　　　　　　　　　　　　　　　　　　THEOREM。



　　　　The　simple　but　empirically　determined　consciousness　of

　　　　　　　my　own　existence　proves　the　existence　of　external

　　　　　　　objects　in　space。



　　　　　　　　　　　　　　　　　　　　　　　　　PROOF



　　I　am　conscious　of　my　own　existence　as　determined　in　time。　All

determination　in　regard　to　time　presupposes　the　existence　of　something

permanent　in　perception。　But　this　permanent　something　cannot　be

something　in　me；　for　the　very　reason　that　my　existence　in　time　is

itself　determined　by　this　permanent　something。　It　follows　that　the

perception　of　this　permanent　existence　is　possible　only　through　a

thing　without　me　and　not　through　the　mere　representation　of　a　thing

without　me。　Consequently；　the　determination　of　my　existence　in　time　is

possible　only　through　the　existence　of　real　things　external　to　me。

Now；　consciousness　in　time　is　necessarily　connected　with　the

consciousness　of　the　possibility　of　this　determination　in　time。

Hence　it　follows　that　consciousness　in　time　is　necessarily　connected

also　with　the　existence　of　things　without　me；　inasmuch　as　the

existence　of　these　things　is　the　condition　of　determination　in　time。

That　is　to　say；　the　consciousness　of　my　own　existence　is　at　the　same

time　an　immediate　consciousness　of　the　existence　of　other　things

without　me。

　　Remark　I。　The　reader　will　observe；　that　in　the　foregoing　proof　the

game　which　idealism　plays　is　retorted　upon　itself；　and　with　more

justice。　It　assumed　that　the　only　immediate　experience　is　internal　and

that　from　this　we　can　only　infer　the　existence　of　external　things。

But；　as　always　happens；　when　we　reason　from　given　effects　to

determined　causes；　idealism　bas　reasoned　with　too　much　haste　and

uncertainty；　for　it　is　quite　possible　that　the　cause　of　our

representations　may　lie　in　ourselves；　and　that　we　ascribe　it　falsely

to　external　things。　But　our　proof　shows　that　external　experience　is

properly　immediate；*　that　only　by　virtue　of　it…　not；　indeed；　the

consciousness　of　our　own　existence；　but　certainly　the　determination　of

our　existence　in　time；　that　is；　internal　experience…　is　possible。　It

is　true；　that　the　representation　〃I　am；〃　which　is　the　expression　of

the　consciousness　which　can　accompany　all　my　thoughts；　is　that　which

immediately　includes　the　existence　of　a　subject。　But　in　this

representation　we　cannot　find　any　knowledge　of　the　subject；　and

therefore　also　no　empirical　knowledge；　that　is；　experience。　For

experience　contains；　in　addition　to　the　thought　of　something　existing；

intuition；　and　in　this　case　it　must　be　internal　intuition；　that　is；

time；　in　relation　to　which　the　subject　must　be　determined。　But　the

existence　of　external　things　is　absolutely　requisite　for　this　purpose；

so　that　it　follows　that　internal　experience　is　itself　possible　only

mediately　and　through　external　experience。



　　*The　immediate　consciousness　of　the　existence　of　external　things　is；

in　the　preceding　theorem；　not　presupposed；　but　proved；　by　the

possibility　of　this　consciousness　understood　by　us　or　not。　The

question　as　to　the　possibility　of　it　would　stand　thus：　〃Have　we　an

internal　sense；　but　no　external　sense；　and　is　our　belief　in　external

perception　a　mere　delusion？〃　But　it　is　evident　that；　in　order　merely

to　fancy　to　ourselves　anything　as　external；　that　is；　to　present　it

to　the　sense　in　intuition　we　must　already　possess　an　external　sense；

and　must　thereby　distinguish　immediately　the　mere　receptivity　of　an

external　intuition　from　the　spontaneity　which　characterizes　every

act　of　imagination。　For　merely　to　imagine　also　an　external　sense；

would　annihilate　the　faculty　of　intuition　itself　which　is　to　be

determined　by　the　imagination。



　　Remark　II。　Now　with　this　view　all　empirical　use　of　our　faculty　of

cognition　in　the　determination　of　time　is　in　perfect　accordance。　Its

truth　is　supported　by　the　fact　that　it　is　possible　to　perceive　a

determination　of　time　only　by　means　of　a　change　in　external

relations　（motion）　to　the　permanent　in　space　（for　example；　we　become

aware　of　the　sun's　motion　by　observing　the　changes　of　his　relation

to　the　objects　of　this　earth）。　But　this　is　not　all。　We　find　that　we

possess　nothing　permanent　that　can　correspond　and　be　submitted　to

the　conception　of　a　substance　as　intuition；　except　matter。　This　idea

of　permanence　is　not　itself　derived　from　external　experience；　but　is

an　a　priori　necessary　condition　of　all　determination　of　time；

consequently　also　of　the　internal　sense　in　reference　to　our　own

existence；　and　that　through　the　existence　of　external　things。　In　the

representation　〃I；〃　the　consciousness　of　myself　is　not　an　intuition；

but　a　merely　intellectual　representation　produced　by　the　spontaneous

activity　of　a　thinking　subject。　It　follows；　that　this　〃I〃　has　not

any　predicate　of　intuition；　which；　in　its　character　of　permanence；

could　serve　as　correlate　to　the　determination　of　time　in　the

internal　sense…　in　the　same　way　as　impenetrability　is　the　correlate　of

matter　as　an　empirical　intuition。

　　Remark　III。　From　the　fact　that　the　existence　of　external　things　is　a

necessary　condition　of　the　possibility　of　a　determined　consciousness

of　ourselves；　it　does　not　follow　that　every　intuitive　representation

of　external　things　involves　the　existence　of　these　things；　for　their

representations　may　very　well　be　the　mere　products　of　the

imagination　（in　dreams　as　well　as　in　madness）；　though；　indeed；　these

are　themselves　created　by　the　reproduction　of　previous　external

perceptions；　which；　as　has　been　shown；　are　possible　only　through　the

reality　of　external　objects。　The　sole　aim　of　our　remarks　has；　however；

been　to　prove　that　internal　experience　in　general　is　possible　only

through　external　experience　in　general。　Whether　this　or　that

supposed　experience　be　purely　imaginary　must　be　discovered　from　its

particular　determinations　and　by　comparing　these　with　the　criteria

of　all　real　experience。



　　Finally；　as　regards　the　third　postulate；　it　applies　to　material

necessity　in　existence；　and　not　to　merely　formal　and　logical　necessity

in　the　connection　of　conceptions。　Now　as　we　cannot　cognize

completely　a　priori　the　existence　of　any　object　of　sense；　though　we

can　do　so　comparatively　a　priori；　that　is；　relatively　to　some　other

previously　given　existence…　a　cognition；　however；　which　can　only　be　of

such　an　existence　as　must　be　contained　in　the　complex　of　experience；

of　which　the　previously　given　perception　is　a　part…　the　necessity　of

existence　can　never　be　cognized　from　conceptions；　but　always；　on　the

contrary；　from　its　connection　with　that　which　is　an　object　of

perception。　But　the　only　existence　cognized；　under　the　condition　of

other　given　phenomena；　as　necessary；　is　the　existence　of　effects

from　given　causes　in　conformity　with　the　laws　of　causality。　It　is

consequently　not　the　necessity　of　the　existence　of　things　（as

substances）；　but　the　necessity　of　the　state　of　things　that　we　cognize；

and　that　not　immediately；　but　by　means　of　the　existence　of　other

states　given　in　perception；　according　to　empirical　laws　of

causality。　Hence　it　follows　that　the　criterion　of　necessity　is　to　be

found　only　in　the　law　of　possible　experience…　that　everything　which

happens　is　determined　a　priori　in　the　phenomenon　by　its　cause。　Thus　we

cognize　only　the　necessity　of　effects　in　nature；　the　causes　of　which

are　given　us。　Moreover；　the　criterion　of　necessity　in　existence

possesses　no　application　beyond　the　field　of　possible　experience；

and　even　in　this　it　is　not　valid　of　the　existence　of　things　as

substances；　because　these　can　never　be　considered　as　empirical

effects；　or　as　something　that　happens　and　has　a　beginning。

Necessity；　therefore；　regards　only　the　relations　of　phenomena

according　to　the　dynamical　law　of　causality；　and　the　possibility

grounded　thereon；　of　reasoning　from　some　given　existence　（of　a

cause）　a　priori　to　another　existence　（of　an　effect）。　〃Everything

that　happens　is　hypothetically　necessary；〃　is　a　principle　which

subjects　the　changes　that　take　place　in　the　world　to　a　law；　that　is；

to　a　rule　of　necessary　existence；　without　which　nature　herself　could

not　possibly　exist。　Hence　the　proposition；　〃Nothing　happens　by　blind

chance　（in　mundo　non　datur　casus）；〃　is　an　a　priori　law　of　nature。

The　case　is　the　same　with　the　proposition；　〃Necessity　in　nature　is　not

blind；〃　that　is；　it　is　conditioned；　consequently　intelligible

necessity　（non　datur　fatum）。　Both　laws　subject　the　play　of　change　to

〃a　nature　of　things　（as　phenomena）；〃　or；　which　is　the　same　thing；　to

the　unity　of　the　understanding；　and　through　the　understanding　alone

can　changes　belong　to　an　experience；　as　the　synthetical　unity　of

phenomena。　Both　belong　to　the　class　of　dynamical　principles。　The

former　is　properly　a　consequence　of　the　principle　of　causality…　one　of

the　analogies　of　experience。　The　latter　belongs　to　the　principles　of

modality；　which　to　the　determination　of　causality　adds　the

conception　of　necessity；　which　is　itself；　however；　subject　to　a　rule

of　the　understanding。　The　principle　of　continuity　forbids　any　leap

in　the　series　of　phenomena　regarded　as　changes　（in　mundo　non　datur

saltus）；　and　likewise；　in　the　complex　of　all　empir