the critique of pure reason-第38节

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order　to　compare　it　synthetically　with　another；　a　third　thing　is

necessary；　in　which　alone　the　synthesis　of　two　conceptions　can

originate。　Now　what　is　this　tertium　quid　that　is　to　be　the　medium　of

all　synthetical　judgements？　It　is　only　a　complex　in　which　all　our

representations　are　contained；　the　internal　sense　to　wit；　and　its　form

a　priori；　time。

　　The　synthesis　of　our　representations　rests　upon　the　imagination；

their　synthetical　unity　（which　is　requisite　to　a　judgement）；　upon

the　unity　of　apperception。　In　this；　therefore；　is　to　be　sought　the

possibility　of　synthetical　judgements；　and　as　all　three　contain　the

sources　of　a　priori　representations；　the　possibility　of　pure

synthetical　judgements　also；　nay；　they　are　necessary　upon　these

grounds；　if　we　are　to　possess　a　knowledge　of　objects；　which　rests

solely　upon　the　synthesis　of　representations。

　　If　a　cognition　is　to　have　objective　reality；　that　is；　to　relate　to

an　object；　and　possess　sense　and　meaning　in　respect　to　it；　it　is

necessary　that　the　object　be　given　in　some　way　or　another。　Without

this；　our　conceptions　are　empty；　and　we　may　indeed　have　thought　by

means　of　them；　but　by　such　thinking　we　have　not；　in　fact；　cognized

anything；　we　have　merely　played　with　representation。　To　give　an

object；　if　this　expression　be　understood　in　the　sense　of　〃to

present〃　the　object；　not　mediately　but　immediately　in　intuition；　means

nothing　else　than　to　apply　the　representation　of　it　to　experience；

be　that　experience　real　or　only　possible。　Space　and　time　themselves；

pure　as　these　conceptions　are　from　all　that　is　empirical；　and

certain　as　it　is　that　they　are　represented　fully　a　priori　in　the　mind；

would　be　completely　without　objective　validity；　and　without　sense

and　significance；　if　their　necessary　use　in　the　objects　of

experience　were　not　shown。　Nay；　the　representation　of　them　is　a　mere

schema；　that　always　relates　to　the　reproductive　imagination；　which

calls　up　the　objects　of　experience；　without　which　they　have　no

meaning。　And　so　it　is　with　all　conceptions　without　distinction。

　　The　possibility　of　experience　is；　then；　that　which　gives　objective

reality　to　all　our　a　priori　cognitions。　Now　experience　depends　upon

the　synthetical　unity　of　phenomena；　that　is；　upon　a　synthesis

according　to　conceptions　of　the　object　of　phenomena　in　general；　a

synthesis　without　which　experience　never　could　become　knowledge；　but

would　be　merely　a　rhapsody　of　perceptions；　never　fitting　together　into

any　connected　text；　according　to　rules　of　a　thoroughly　united

（possible）　consciousness；　and　therefore　never　subjected　to　the

transcendental　and　necessary　unity　of　apperception。　Experience　has

therefore　for　a　foundation；　a　priori　principles　of　its　form；　that　is

to　say；　general　rules　of　unity　in　the　synthesis　of　phenomena；　the

objective　reality　of　which　rules；　as　necessary　conditions　even　of

the　possibility　of　experience　can　which　rules；　as　necessary

conditions…　even　of　the　possibility　of　experience…　can　always　be　shown

in　experience。　But　apart　from　this　relation；　a　priori　synthetical

propositions　are　absolutely　impossible；　because　they　have　no　third

term；　that　is；　no　pure　object；　in　which　the　synthetical　unity　can

exhibit　the　objective　reality　of　its　conceptions。

　　Although；　then；　respecting　space；　or　the　forms　which　productive

imagination　describes　therein；　we　do　cognize　much　a　priori　in

synthetical　judgements；　and　are　really　in　no　need　of　experience　for

this　purpose；　such　knowledge　would　nevertheless　amount　to　nothing

but　a　busy　trifling　with　a　mere　chimera；　were　not　space　to　be

considered　as　the　condition　of　the　phenomena　which　constitute　the

material　of　external　experience。　Hence　those　pure　synthetical

judgements　do　relate；　though　but　mediately；　to　possible　experience；　or

rather　to　the　possibility　of　experience；　and　upon　that　alone　is

founded　the　objective　validity　of　their　synthesis。

　　While　then；　on　the　one　hand；　experience；　as　empirical　synthesis；

is　the　only　possible　mode　of　cognition　which　gives　reality　to　all

other　synthesis；　on　the　other　hand；　this　latter　synthesis；　as

cognition　a　priori；　possesses　truth；　that　is；　accordance　with　its

object；　only　in　so　far　as　it　contains　nothing　more　than　what　is

necessary　to　the　synthetical　unity　of　experience。

　　Accordingly；　the　supreme　principle　of　all　synthetical　judgements　is：

〃Every　object　is　subject　to　the　necessary　conditions　of　the

synthetical　unity　of　the　manifold　of　intuition　in　a　possible

experience。〃

　　A　priori　synthetical　judgements　are　possible　when　we　apply　the

formal　conditions　of　the　a　priori　intuition；　the　synthesis　of　the

imagination；　and　the　necessary　unity　of　that　synthesis　in　a

transcendental　apperception；　to　a　possible　cognition　of　experience；

and　say：　〃The　conditions　of　the　possibility　of　experience　in　general

are　at　the　same　time　conditions　of　the　possibility　of　the　objects　of

experience；　and　have；　for　that　reason；　objective　validity　in　an　a

priori　synthetical　judgement。〃



　　　　　SECTION　III。　Systematic　Representation　of　all　Synthetical

　　　　　　　　　　　　　Principles　of　the　Pure　Understanding。



　　That　principles　exist　at　all　is　to　be　ascribed　solely　to　the　pure

understanding；　which　is　not　only　the　faculty　of　rules　in　regard　to

that　which　happens；　but　is　even　the　source　of　principles　according

to　which　everything　that　can　be　presented　to　us　as　an　object　is

necessarily　subject　to　rules；　because　without　such　rules　we　never

could　attain　to　cognition　of　an　object。　Even　the　laws　of　nature；　if

they　are　contemplated　as　principles　of　the　empirical　use　of　the

understanding；　possess　also　a　characteristic　of　necessity；　and　we

may　therefore　at　least　expect　them　to　be　determined　upon　grounds　which

are　valid　a　priori　and　antecedent　to　all　experience。　But　all　laws　of

nature；　without　distinction；　are　subject　to　higher　principles　of　the

understanding；　inasmuch　as　the　former　are　merely　applications　of　the

latter　to　particular　cases　of　experience。　These　higher　principles

alone　therefore　give　the　conception；　which　contains　the　necessary

condition；　and；　as　it　were；　the　exponent　of　a　rule；　experience；　on　the

other　hand；　gives　the　case　which　comes　under　the　rule。

　　There　is　no　danger　of　our　mistaking　merely　empirical　principles

for　principles　of　the　pure　understanding；　or　conversely；　for　the

character　of　necessity；　according　to　conceptions　which　distinguish　the

latter；　and　the　absence　of　this　in　every　empirical　proposition；　how

extensively　valid　soever　it　may　be；　is　a　perfect　safeguard　against

confounding　them。　There　are；　however；　pure　principles　a　priori；

which　nevertheless　I　should　not　ascribe　to　the　pure　understanding…　for

this　reason；　that　they　are　not　derived　from　pure　conceptions；　but

（although　by　the　mediation　of　the　understanding）　from　pure　intuitions。

But　understanding　is　the　faculty　of　conceptions。　Such　principles

mathematical　science　possesses；　but　their　application　to　experience；

consequently　their　objective　validity；　nay　the　possibility　of　such　a

priori　synthetical　cognitions　（the　deduction　thereof）　rests　entirely

upon　the　pure　understanding。

　　On　this　account；　I　shall　not　reckon　among　my　principles　those　of

mathematics；　though　I　shall　include　those　upon　the　possibility　and

objective　validity　a　priori；　of　principles　of　the　mathematical

science；　which；　consequently；　are　to　be　looked　upon　as　the　principle

of　these；　and　which　proceed　from　conceptions　to　intuition；　and　not

from　intuition　to　conceptions。

　　In　the　application　of　the　pure　conceptions　of　the　understanding　to

possible　experience；　the　employment　of　their　synthesis　is　either

mathematical　or　dynamical；　for　it　is　directed　partly　on　the

intuition　alone；　partly　on　the　existence　of　a　phenomenon。　But　the　a

priori　conditions　of　intuition　are　in　relation　to　a　possible

experience　absolutely　necessary；　those　of　the　existence　of　objects

of　a　possible　empirical　intuition　are　in　themselves　contingent。

Hence　the　principles　of　the　mathematical　use　of　the　categories　will

possess　a　character　of　absolute　necessity；　that　is；　will　be

apodeictic；　those；　on　the　other　hand；　of　the　dynamical　use；　the

character　of　an　a　priori　necessity　indeed；　but　only　under　the

condition　of　empirical　thought　in　an　experience；　therefore　only

mediately　and　indirectly。　Consequently　they　will　not　possess　that

immediate　evidence　which　is　peculiar　to　the　former；　although　their

application　to　experience　does　not；　for　that　reason；　lose　its　truth

and　certitude。　But　of　this　point　we　shall　be　better　able　to　judge　at

the　conclusion　of　this　system　of　principles。

　　The　table　of　the　categories　is　naturally　our　guide　to　the　table　of

principles；　because　these　are　nothing　else　than　rules　for　the

objective　employment　of　the　former。　Accordingly；　all　principles　of　the

pure　understanding　are：



　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　1

　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　Axioms

　　　　　　　　　　　　　　　　　　　　　　　　　　　of　Intuition



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