Leibniz：Metaphysical Consequences of the Principle of Reason (1712)

Leibniz :Principium ratiocinandi fundamentale est , nihil esse sine ratione,... (1712)

Leibniz：

Metaphysical Consequences of the Principle of Reason (1712)

（ライプニッツ「理由律からの形而上学的帰結」）

　I. The fundamental Principle of reasoning is that there is
nothing without a reason ;or，to explain the matter more dis-
tinctly，that there is no truth for which a reason does not
subsist.The rcason for a truth consists in the conncxion of
the Predicate with the subject， that is， that the Predicate is in
the su司cct.This is either mani拓ｓｔ，ａｓ ｉｎ ｔｈｅ ｃａｓｅ ｏｆ ｉｄｅｎｔｉｃａｌ
ＰｒｏＰｏｓｉｔｉｏｎｓ--ｆｏｒ ｅｘａｍＰｌｅ， ｀Ａ ｍａｎ ｉｓ ａ ｍａｎ゛， ｏｒ ‘Ａ ｗｈｉｔｅ
ｍａｎ ｉｓ ｗｈｉｔｅ'?,。ｒ ｉｔ ｉｓ ｃｏｎｃｅａｌｅｄ， ｂｕｔ ｃｏｎｃｅａｌｅｄ ｉｎｓｕｃｈ ａ ｗａｙ
ｔｈａｔ ｔｈｅｃｏｎｎｅｘｉｏｎ ｃａｎｂｅ ｓｈｏｗｎ ｂｙ ｔｈｅａｎａｌｙｓｉｓ ｏｆ ｎｏｔｉｏｎｓ一
応r examPle/ Nine is a square'. For nine is three times three，
which is three multiplied by three， which isa nunlber multi-
Plied by itself; which is a square.
　2. This PrinciPle disPosesof all inexPlicable occult qualities，
and other similar ngments. For as ofienas vvriters introduce
some Primitiveoccult quality they imPillge on this princiPle.
ForexanlPle，suPPose that someone thinks that there is in
nlatter sorneattractive force which is Primitive， and there-
fore　not　derivable from　the　intelligible　notionsof body
(namely，magnitude， shaPe and motion).And suPpose he
wants it to haPPen that by this attractive fi)rce bodies tend
to゛ards some other body without being Pushed， assorne
conceive gravity-namcly， as if heavy things were attracted
by the body of the eal'thj or as if they were attracted to it by
some symPathy， insuch a way that the ulteriorreasonof this
cannot be given 仔om the nature of bodies， and the method or
attraction ca“lot be eM)hlined. Such a Personadmits that
there is no reason for the truth that a stone tends towards the
earth･ Fol｀if he thillks th21t this occurs， not by an occult
quality of the body5 but by the will of God or by a divinely
estabnshed law， by that very fact he givessonle reason，but a
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suPernatural or miraculous one.The same is to be said of a11
those who， where bodily Phenomena a17e to be exPlained， have
recourse to bal｀e faculties， symPathies， antiPathies，arch3ei,3
operatiollal ideas， Plastic fi)rce，so111s alld other incorPoreal
entities，which(as they have to admit)have no connexion
with the Phenornenon.
　3. The consequcnceof this is that in thecaseof bodies
everythingoccurs nlechanically，that is， through the intc1-
ngible qualities of bodies， namely magnitude， shaPe and
motion; in thecaseofsouls，everything is to be explained in
vital terms， that is， through the intelligible qualities of the
soul，namely PerccPtions and aPPetites. However，we detect
in alli“lated bodies a bealltif111 h21mlolly between vitality
and mechanism， such that what occurs mechanically in the
body is rePresented vitally in thesou1; and what are Per-
ceived exactly in thesoul are handed over comPletely fi)｢
execution in the body.
　4. From this it fi)11ows that we call onen heal thesoul fiom
the known qualities or the body， andcanonell heal the body
fiヽom the known aflilctions of the sou1. For it is o丘en easier to
know what haPPens in thesoul than what haPPens in the
body; ofien， again，the contrary is thecase.As oRen as we
use what thesoul indicates to he1P the body， this may be
called vital medicine;　this extends more widely than is
commonly thought. For the body corresPOIlds to the soul
not only in the so-called voluntary motions， but in all others
as well; though， on account of habit， we do not notice that the
soul is aflkcted by or agrees with the motionsof the body， or
that the latter corresPond to the Perceptions and aPPetites
of thesoul. For the PercePtionsof these are confused， so that
their agreement does not aPPear soeasily.Thesoul gives
orders to the body in so nlr as it has distinct PercePtions， and
serves it in so fllr as it has confused ones; however， anyone
who hassorneperceptioll in hissoul can be certain that he
has received some emごct of that in his body， and vice versa.
XVhatever is good， then，in the archaeists or similar writers
is reduced to this; 拓revenif there do not exist in the body
the disturbances of thearchaeus(which they say are anger)
and its setdings， and these cannot beconceived excePt as in
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thesou1，yet there is something in the body which corresPonds
to these.
　5. Furtherjt is a fllct that we can sometimes arrive at the
truth about natulヽal things through final causes， when we
cannot arrive at it easily through emcient causes. This is
shown，not only by the anatomical doctrine of theuseofthe
members，where xve reasoncorrectly fiom the end to the
means，but also (as l myselfhaveshown)by a notable examPle
in oPtics.b For just as in animated bodies what is organic
corresponds to what is vital， motions to aPpetites， so also in
the whole of nature　emcicnt causes　corresPond　to final
causes}becauseeverything Proceeds 丘orn a causewhich isnot
only Powernllj but also wise; and with the rule of power
through emcient causes， there is involved the rule of ゛isdom
through nnalcauses.This harmony of corporeal and sPiritual
is one of the fillest and most evident argllmellts for a Divinity；
fi)r，since the innux of one kind on another is inexPlicable， a
harmony of thillgs which are entirely diflkrent can arise only
fi･om theone conlnlon cause，that is， God.
　6. But we shall arrive at the same Point in a more general
way by returning to our fundamentaI PrinciPle. VVe must
renect that sPace， time and matter-bare matter， in which
nothing is considered besides extension and impenetrabilityc-
are dearly indifＲrent with resPect to any magnitudes， shapes
and motions.Consequently no reason can be foundjn these
indiflerent and indeterminate things， fi)r what is determinate；
that is， why the world should exist insuch and such a way，
and should not have been Produced in any other noless
Possible form. Theconsequenceof this is that thereason柘r
the e｀istence of colltingent things must eventually besought
olltside mattel｀alld in a necessary cause; namely， in that
whose reason for existing is not outside itse1£This，therefi)re，
is sPiritual-in a word， a mind-and is also the most perfkct
mind，since on account of the connexion of things it extends
to a11.
　7.Further，all creatures are either substantial or accidental.
Those which are substantial are either substances or sub-
stantiated. l give the name ‘sllbstantiated'd to aggregates of
substances，such as an army of men， or a nock of sheeP; and

175
all bodies are such aggregates. A substance is either silnpie，
such as a sou1， which has noParts，or it is comPosit(ちsuch as
an anima1， which consists ofasoul and an organic body. But
an organic body， 1ikeevery other body， is merely an aggre-
gate of animals or other things ゛hich are li゛ing and theren)17e
organic，or nnally of sm2111 objects or masscs; but these also
are nnally resolved into living things， fiolll ゛hich it is e゛ident
that all bodies are nnally resolved into living things5 and that
whatjn theanalysis of substances， exist ultimatelyaresimPle
substances-namely，souls，or，if you Preｌr a lnoregenel｀al
term，ｱﾌ?θyz?J，which are without Parts.　For even though
every simple substallce hasanorganic body whichcorres-
Ponds to it-other゛ise it would not have ally killd of orderly
relation to other things ill the universe5nor xvould it act or be
acted uPon in an ordcrly ゛ay-yet by itself it is without
parts. And because an orgallic body3　or ally other body
whatsoever，canagain be reso1゛ed illto sllbstances endowed
with organic bodies， it is evident that in the end there are
simPlesubstancesalone，andthat in them arethe sources of
all things and of the modmcations that come to things.
　8.But because lnodincations vary，and whatever is the
sourceof variations is truly active， it must therefore be said
that simPle substallces are active or thesourcesof actionsﾀ
and that they Produce in themselves a certaill sel｀ies ofinternal
variations.And because there isnolneansby whichonesimple
substance could innuence anotherjt follows that every simple
substance is sPontaneous3 or theone and onlysourceof its
own modincations.Further，since the nature of a simPle
substance consists of PercePtionand apPetite， it is clear that
there is ineach soul a scries of aPPetites and percePtions，
through which it is led 仔ｏｍ ｔｈｅ ｅｎｄ ｔｏ ｔｈｅ ｍｅａｎｓ， ｎヽｏｍ ｔｈｅ
ｐｅｌｃｅＰｔｉｏｎ ｏｆ ｏｌｌｅ ｏｂｊｃｃｔ ｔｏ ｔｈｅ ＰｅｒｃｅＰｔｉｏｎ ｏｆ ａｎｏｔｈｅｒ． Ｓｏ ｔｈｅ
ｓｏｕｌ ｄｏｅｓ ｎｏｔ ｄｅｐｅｎｄｏｎ ａｎｙｔｈｉｎｇ ｅｘｃｅＰｔ ａ ｕｎｉｖｅｒｓａｌ ｃａｕｓｅﾀ
or God， through whom (like all things)it continually exists
and is conserved; but the rest it has liom its own nature.
　9. But there would be no orderanlong these simPle sub'
stances，which lack the interchange of mutual innux3 unless
they at least corresPOIlded to each other mutllally. Hence it is
necessary that there is between them a certain relation of

176　　　　
perceptions orphenonlena，through which it can be discerned
how much their modincations difRir fFom each other in
sPace or tiIIle; fi)r in these two-time and Place?-there con-
sists the order of things which exist either successively or
sim?taneously. From this it also follows that every simPle
substance rePresents an aggregate of external things， and that
in those e｀ternal things， rePresented in diverse ways， there
consists both the diversity and the harmony of souls. Each
soul wi11 rePrescnt Proximately the phenornenaof its own
orgallic body， but remotely thoseof others which act on its
own body･
　　lo. lt mustjalso be known that， because of the nature of
things，in the whole of the univcrse ‘all things consPire゛， as
HiPPocrates says of the body ofananimal，and everything
collsPil｀es with e゛el｀ythillg else in a certain nxed way. For
sincea1I Places al｀e nlled with bodies， and all bodies are en-
dowed｀゛ith a certaill degl｀ee of nuidity， so that they give way
somewhat to Pressure， hoxvever snla11，it follows 丘om this
that no body can be moved without its neighbour being
moved somewhat， and，fi)r the same reason， the neighbour
of its neighbour， and soon over any distance， hoxvevergreat.
From this it follows that each corPusde is acted on by all
the bodies in the universe， and is variously aflicted by them，
in such a way that the omniscient being knows， in each
Particle of the ulliverse， everything which haPPens in the
entire universe. Thiscould not haPPenunless matter were
everywhere di゛isible， and indeed actually divided ?fzz-
鳶7面詞.There拓re，since every organic body is afkcted by the
entire universeby relations which are determinate with res-
Pect to each part of the universejt is not surprising that the
sou1，which represents to itself the rest in accordance with the
relationsofits bodyjs a kind ofmirror ofthe universe， which
rePresents the rest in accordance with (so to speak)its Point
ofview?just as thesanlecity P゛esell喘to a person who looks
at it fi-om varioussides，Pr(!jectiorls which are quite dimうrent.
　　I I. But it must not be thought that， when l sPeak of a
mirror，l mean that external thingsarealways dePicted in
the organs and in thesoul itselfl For it is sumcient for the
exPression()f one thing in 211other that thereshould be a

177
certain constant re121tional law， by which Particulars in the
one can be refi2rred to corresPonding Particulars in the other.e
Thus，a cirdecanbe rePresented by an emPse (that is， an
oval cu“e)in a PersPccti゛a1 P｢(t｣ectiol15 and indeed by a
hyPerbola，which is most unlike it， and does not even return
uPon itself; fi)r to any poillt of the hyperbola a corresponding
Point ofthe circle ゛hich pl7(!jects the hyPerbolacanbe assigned
by the same constant law. From this it comes about that a
created　soul　necessarily　has　many　confused　PercePtions，
rePresenting an aggregation of innulnerable external things，
but it Perceives distinctly what is closeror nloreprominentﾀ
and accommodated to its organs.But since it also under-
standsreasons，the mind is not only a mirror of the created
universe，but is also an image of God. Bllt this belongs to
rational substances alone.
　　12. From this it fo11ows that a simPle substance does not
come into existellce natuially(゛nless ゛ith the oligin of
things)，nor can it cease to exist， but it always relllains the
same. For since it does not have Parts， it cannot suner dis'
golution; since it is thesourceof variations， it Proceeds in a
continuousseriesofchange;andsillcebyitso゛nnatureifisa
mirror of the universe， itno nlore ceases toexist than the
universe itselfl But if it should arrive at that state in which
it has PcrcePtions whicharealmost all confused， we call this
｀death≒fi)r then a stuPor arises， as in a Profoulld sleeP or in
apoPle｀y.　But since natごe Fadllally u=avelscon丘1sions，
then that which we suPPose to be dcath cannot be PerPeula1.
But is is only rational substances which Preserve， not only
their individuality， but also their Personality， by retaining or
recovering consciousnessof themselves， so that they can be
citizens in the city of God， caPable of reward and punish-
ment･ ln them， thercらre，the kingdom of naulre serves the
kingdom of grace.f
　　l3. 1ndeed l go伍rther， and l assert that not ollly thesoul
but also the animal itself lasts PerPetually， fi｀om the vcry
beginning of things. For a soul is always elldo゛ed ゛ith an
organic body， so th21t it has that thlough ゛hich it IIlay l｀ep'
resent the other e｀ternal things in an ordel｀1y way; alld so its
body can indeed be reduced to a great nneness， but cannot be

178　　　　
utterly destroyed. And though it may be that the body con-
sists of a perPetual nll｀5 alld it callnot be said that any Pal'ticle
of matter is constantly assigned to thesarne soul，yet an entire
organic bodycan neverbe given to or taken away fiom the
sou1.Hoxvever nluch the anilllal gl｀o゛s at concePtion， yet it
had a seminal organism before it could be brought forth
through concePtionand could grow; and hoxvever nluch it
may diminish at death， yet once its skin has been cast， it
retains a subtle organism suPerior to all the fi)rcesof nature，
since it extends to innnity through rePeated subdivisions. For
since nature has been made by a most wise artincer， it is
everywhere orgallic within， and the organism of living things
is nothing other than a divine mechanism， increasing in
subtlety to infinity. Noonenttingly understands the works of
God unless he sumcientlyrecognises in them this fllct: that
the enect is the trace of its cause.