the critique of pure reason-第26节

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　　Among　the　many　conceptions；　which　make　up　the　very　variegated　web　of

human　cognition；　some　are　destined　for　pure　use　a　priori；

independent　of　all　experience；　and　their　title　to　be　so　employed

always　requires　a　deduction；　inasmuch　as；　to　justify　such　use　of　them；

proofs　from　experience　are　not　sufficient；　but　it　is　necessary　to　know

how　these　conceptions　can　apply　to　objects　without　being　derived

from　experience。　I　term；　therefore；　an　examination　of　the　manner　in

which　conceptions　can　apply　a　priori　to　objects；　the　transcendental

deduction　of　conceptions；　and　I　distinguish　it　from　the　empirical

deduction；　which　indicates　the　mode　in　which　conception　is　obtained

through　experience　and　reflection　thereon；　consequently；　does　not

concern　itself　with　the　right；　but　only　with　the　fact　of　our　obtaining

conceptions　in　such　and　such　a　manner。　We　have　already　seen　that　we

are　in　possession　of　two　perfectly　different　kinds　of　conceptions；

which　nevertheless　agree　with　each　other　in　this；　that　they　both　apply

to　objects　completely　a　priori。　These　are　the　conceptions　of　space　and

time　as　forms　of　sensibility；　and　the　categories　as　pure　conceptions

of　the　understanding。　To　attempt　an　empirical　deduction　of　either　of

these　classes　would　be　labour　in　vain；　because　the　distinguishing

characteristic　of　their　nature　consists　in　this；　that　they　apply　to

their　objects；　without　having　borrowed　anything　from　experience

towards　the　representation　of　them。　Consequently；　if　a　deduction　of

these　conceptions　is　necessary；　it　must　always　be　transcendental。

　　Meanwhile；　with　respect　to　these　conceptions；　as　with　respect　to　all

our　cognition；　we　certainly　may　discover　in　experience；　if　not　the

principle　of　their　possibility；　yet　the　occasioning　causes　of　their

production。　It　will　be　found　that　the　impressions　of　sense　give　the

first　occasion　for　bringing　into　action　the　whole　faculty　of

cognition；　and　for　the　production　of　experience；　which　contains　two

very　dissimilar　elements；　namely；　a　matter　for　cognition；　given　by　the

senses；　and　a　certain　form　for　the　arrangement　of　this　matter；　arising

out　of　the　inner　fountain　of　pure　intuition　and　thought；　and　these；　on

occasion　given　by　sensuous　impressions；　are　called　into　exercise　and

produce　conceptions。　Such　an　investigation　into　the　first　efforts　of

our　faculty　of　cognition　to　mount　from　particular　perceptions　to

general　conceptions　is　undoubtedly　of　great　utility；　and　we　have　to

thank　the　celebrated　Locke　for　having　first　opened　the　way　for　this

inquiry。　But　a　deduction　of　the　pure　a　priori　conceptions　of　course

never　can　be　made　in　this　way；　seeing　that；　in　regard　to　their

future　employment；　which　must　be　entirely　independent　of　experience；

they　must　have　a　far　different　certificate　of　birth　to　show　from

that　of　a　descent　from　experience。　This　attempted　physiological

derivation；　which　cannot　properly　be　called　deduction；　because　it

relates　merely　to　a　quaestio　facti；　I　shall　entitle　an　explanation

of　the　possession　of　a　pure　cognition。　It　is　therefore　manifest　that

there　can　only　be　a　transcendental　deduction　of　these　conceptions

and　by　no　means　an　empirical　one；　also；　that　all　attempts　at　an

empirical　deduction；　in　regard　to　pure　a　priori　conceptions；　are　vain；

and　can　only　be　made　by　one　who　does　not　understand　the　altogether

peculiar　nature　of　these　cognitions。

　　But　although　it　is　admitted　that　the　only　possible　deduction　of　pure

a　priori　cognition　is　a　transcendental　deduction；　it　is　not；　for

that　reason；　perfectly　manifest　that　such　a　deduction　is　absolutely

necessary。　We　have　already　traced　to　their　sources　the　conceptions

of　space　and　time；　by　means　of　a　transcendental　deduction；　and　we　have

explained　and　determined　their　objective　validity　a　priori。

Geometry；　nevertheless；　advances　steadily　and　securely　in　the　province

of　pure　a　priori　cognitions；　without　needing　to　ask　from　philosophy

any　certificate　as　to　the　pure　and　legitimate　origin　of　its

fundamental　conception　of　space。　But　the　use　of　the　conception　in　this

science　extends　only　to　the　external　world　of　sense；　the　pure　form

of　the　intuition　of　which　is　space；　and　in　this　world；　therefore；

all　geometrical　cognition；　because　it　is　founded　upon　a　priori

intuition；　possesses　immediate　evidence；　and　the　objects　of　this

cognition　are　given　a　priori　（as　regards　their　form）　in　intuition　by

and　through　the　cognition　itself。　With　the　pure　conceptions　of

understanding；　on　the　contrary；　commences　the　absolute　necessity　of

seeking　a　transcendental　deduction；　not　only　of　these　conceptions

themselves；　but　likewise　of　space；　because；　inasmuch　as　they　make

affirmations　concerning　objects　not　by　means　of　the　predicates　of

intuition　and　sensibility；　but　of　pure　thought　a　priori；　they　apply　to

objects　without　any　of　the　conditions　of　sensibility。　Besides；　not

being　founded　on　experience；　they　are　not　presented　with　any　object　in

a　priori　intuition　upon　which；　antecedently　to　experience；　they

might　base　their　synthesis。　Hence　results；　not　only　doubt　as　to　the

objective　validity　and　proper　limits　of　their　use；　but　that　even　our

conception　of　space　is　rendered　equivocal；　inasmuch　as　we　are　very

ready　with　the　aid　of　the　categories；　to　carry　the　use　of　this

conception　beyond　the　conditions　of　sensuous　intuition…　and；　for

this　reason；　we　have　already　found　a　transcendental　deduction　of　it

needful。　The　reader；　then；　must　be　quite　convinced　of　the　absolute

necessity　of　a　transcendental　deduction；　before　taking　a　single　step

in　the　field　of　pure　reason；　because　otherwise　he　goes　to　work

blindly；　and　after　he　has　wondered　about　in　all　directions；　returns　to

the　state　of　utter　ignorance　from　which　he　started。　He　ought；

moreover；　clearly　to　recognize　beforehand　the　unavoidable　difficulties

in　his　undertaking；　so　that　he　may　not　afterwards　complain　of　the

obscurity　in　which　the　subject　itself　is　deeply　involved；　or　become

too　soon　impatient　of　the　obstacles　in　his　path；　because　we　have　a

choice　of　only　two　things…　either　at　once　to　give　up　all　pretensions

to　knowledge　beyond　the　limits　of　possible　experience；　or　to　bring

this　critical　investigation　to　completion。

　　We　have　been　able；　with　very　little　trouble；　to　make　it

comprehensible　how　the　conceptions　of　space　and　time；　although　a

priori　cognitions；　must　necessarily　apply　to　external　objects；　and

render　a　synthetical　cognition　of　these　possible；　independently　of　all

experience。　For　inasmuch　as　only　by　means　of　such　pure　form　of

sensibility　an　object　can　appear　to　us；　that　is；　be　an　object　of

empirical　intuition；　space　and　time　are　pure　intuitions；　which　contain

a　priori　the　condition　of　the　possibility　of　objects　as　phenomena；　and

an　a　priori　synthesis　in　these　intuitions　possesses　objective

validity。

　　On　the　other　hand；　the　categories　of　the　understanding　do　not

represent　the　conditions　under　which　objects　are　given　to　us　in

intuition；　objects　can　consequently　appear　to　us　without　necessarily

connecting　themselves　with　these；　and　consequently　without　any

necessity　binding　on　the　understanding　to　contain　a　priori　the

conditions　of　these　objects。　Thus　we　find　ourselves　involved　in　a

difficulty　which　did　not　present　itself　in　the　sphere　of

sensibility；　that　is　to　say；　we　cannot　discover　how　the　subjective

conditions　of　thought　can　have　objective　validity；　in　other　words；　can

become　conditions　of　the　possibility　of　all　cognition　of　objects；

for　phenomena　may　certainly　be　given　to　us　in　intuition　without　any

help　from　the　functions　of　the　understanding。　Let　us　take；　for

example；　the　conception　of　cause；　which　indicates　a　peculiar　kind　of

synthesis；　namely；　that　with　something；　A；　something　entirely

different；　B；　is　connected　according　to　a　law。　It　is　not　a　priori

manifest　why　phenomena　should　contain　anything　of　this　kind　（we　are　of

course　debarred　from　appealing　for　proof　to　experience；　for　the

objective　validity　of　this　conception　must　be　demonstrated　a

priori）；　and　it　hence　remains　doubtful　a　priori；　whether　such　a

conception　be　not　quite　void　and　without　any　corresponding　object

among　phenomena。　For　that　objects　of　sensuous　intuition　must

correspond　to　the　formal　conditions　of　sensibility　existing　a　priori

in　the　mind　is　quite　evident；　from　the　fact　that　without　these　they

could　not　be　objects　for　us；　but　that　they　must　also　correspond　to　the

conditions　which　understanding　requires　for　the　synthetical　unity　of

thought　is　an　assertion；　the　grounds　for　which　are　not　so　easily　to　be

discovered。　For　phenomena　might　be　so　constituted　as　not　to　correspond

to　the　conditions　of　the　unity　of　thought；　and　all　things　might　lie　in

such　confusion　that；　for　example；　nothing　could　be　met　with　in　the

sphere　of　phenomena　to　suggest　a　law　of　synthesis；　and　so　correspond

to　the　conception　of　cause　and　effect；　so　that　this　conception　would

be　quite　void；　null；　and　without　significance。　Phenomena　would

nevertheless　continue　to　present　objects　to　our　intui