Aristotle
About [Greek: to\ metabiba/zein], compare Topica, I. ii. p. 101, a.
23.]
[Footnote 428: Ibid. b. 2: [Greek: o(/ te ga\r e)ristikô=s e)rôtô=n
phau/lôs diale/getai, o(/ t' e)n tô=| a)pokri/nesthai mê\ didou\s ta\
phaino/menon mêd' e)kdecho/menos o(/ ti/ pote bou/letai o( e)rôtô=n
puthe/sthai.]]
[Footnote 429: Topic. VIII. xi. p. 161, b. 11-18: [Greek: e)pei\ d'
e)sti\n a)dio/riston po/te ta)nanti/a kai\ po/te ta\ e)n a)rchê=|
lamba/nousin oi( a)/nthrôpoi (polla/kis ga\r kath' au(tou\s le/gontes
ta)nanti/a le/gousi, kai\ a)naneu/santes pro/teron dido/asin
u(/steron; dio/per e)rôtô/menoi ta)nanti/a kai\ to\ e)n a)rchê=|
polla/kis u(pakou/ousin)--a)na/gkê phau/lous gi/nesthai tou\s
lo/gous; ai)/tios d' o( a)pokrino/menos, ta\ me\n ou) didou/s, ta\
de\ toiau=ta didou/s.]
This passage is not very clear.]
Such then are the cases in which the conduct of the dialogue is open
to censure, without any fault on your part as questioner. But there
are other cases in which the fault is really yours. These are five in
number:--(1) When all or most of your questions are so framed as to
elicit premisses either false or improbable, so that neither the
conclusion which you seek to obtain, nor any other conclusion at all,
follows from them; (2) When, from similar defects, the proper
conclusion that you seek to obtain cannot be drawn from your
premisses; (3) When the proper conclusion would follow, if certain
additions were made to your premisses, but such additions are of a
character worse than the premisses already obtained, and are even
less probable than the conclusion itself; (4) When you have
accumulated a superfluous multitude of premisses, so that the proper
conclusion does not follow from all of them but from a part of them
only (5) When your premisses are more improbable and less trustworthy
than the proper conclusion, or when, though true, they are harder and
more troublesome to prove than the problem itself.[430]
[Footnote 430: Ibid. b. 19-33: [Greek: kath' au(to\n de\ tô=| lo/gô|
pe/nte ei)si\n e)pitimê/seis].]
In regard to the last item, however, the fault may sometimes be in
the problem itself rather than in you as questioner. Some problems,
being in their own nature hard and not to be settled from probable or
plausible data, ought not to be admitted into Dialectic. All that can
be required from you as questioner is that you shall know and obtain
the most probable premisses that the problem admits: your procedure
may be thus in itself blameable, yet it may even deserve praise,
having regard to the problem, if this last be very intractable; or it
may be in itself praiseworthy, yet blameable in regard to the
problem, if the problem admit of being settled by premisses still
more probable.[431] You may even be more blameable, if you obtain
your conclusion but obtain it from improbable premisses, than if you
failed to obtain it; the premisses required to make it complete being
true and probable and not of capital importance, but being refused by
the respondent.[432] However, you ought not to be blamed if you
obtain your true and proper conclusion but obtain it through
premisses in themselves false; for this is recognized in analytical
theory as possible: if the conclusion is false, the premisses (one or
both) must be false, but a true conclusion may be drawn from false
premisses.[433]
[Footnote 431: Ibid. b. 34-p. 162, a. 3.]
[Footnote 432: Ibid. p. 162, a. 3-8.]
[Footnote 433: Topic. VIII. xi. p. 162, a. 8-11: [Greek: toi=s de\
dia\ pseudô=n a)lêthe\s sumperainome/nois ou) di/kaion e)pitima=n--
phanero\n d' e)k tô=n A)nalutikô=n.]]
When you have obtained your premisses and proved a conclusion, these
same premisses will not serve as proof of any other proposition
separate and independent of the conclusion; such may sometimes seem
to be the case, but it is a mere sophistical delusion. If your
premisses are both of them probable, your conclusion may in some
cases be more probable than either.[434]
[Footnote 434: Ibid. a.12-24.
Aristotle here introduces four definitions of terms, which are useful
in regard to his thoughts but have no great pertinence in the place
where they occur: [Greek: e)/sti de\ _philoso/phêma_ me\n
sullogismo\s a)podeiktiko/s, _e)pichei/rêma_ de\ sullogismo\s
dialektiko/s, _so/phisma_ de\ sullogismo\s e)ristiko/s, _a)po/rêma_
de\ sullogismo\s dialektiko\s a)ntipha/seôs.]]
One other matter yet remains in which your procedure as questioner
may be blameable. The premisses through which you prove your
conclusion may be long and unnecessarily multiplied; the conclusion
may be such that you ought to have obtained it through fewer, yet
equally pertinent premisses.[435]
[Footnote 435: Ibid. a. 24-34.
The example whereby Aristotle illustrates this position is obscure
and difficult to follow. It is borrowed from the Platonic theory of
Ideas. The point which you are supposed to be anxious to prove is,
that one opinion is more opinion than another ([Greek: o(/ti e)sti\
do/xa ma=llon e(te/ra e(te/ras]). To prove it you ask as premisses:
(1) That the Idea of every class of things is more that thing than
any one among the particulars of the class; (2) That there is an Idea
of _matter of opinion_, and that this Idea is more opinion than any
one of the particular matters of opinion. If this Idea is more
opinion, it must also be more true and accurate than any particular
matter of opinion. And it is this last conclusion that Aristotle
seems to indicate as the conclusion to be proved: [Greek: ô(/ste
au(tê\ ê( do/xa a)kribeste/ra e)sti/n] (a. 32).
As I understand it, Aristotle supposes that the doctrine which you
are here refuting is, that all [Greek: e)/ndoxa] are on an equal
footing as to truth and accuracy; and that the doctrine which you are
proving against it is, that one [Greek: e)/ndoxon] is more true and
accurate than another. If you attempt to prove this last by invoking
the Platonic theory of Ideas, you will introduce premisses
far-fetched and unnecessary, even if true; whereas you might prove
your conclusion from premisses easier and more obvious.
The fault is (he says) that such roundabout procedure puts out of
sight the real ground of the proof: [Greek: ti/s de\ ê( mochthêri/a?
ê)\ o(/ti poiei=, par' o(\ o( lo/gos, lantha/nein to\ ai)/tion] (a.
33). The dubitative and problematical form here is remarkable. How
would Aristotle himself have proved the above conclusion? By
Induction? He does not tell us.]
The cases in which your argument will carry the clearest evidence,
impressing itself even on the most vulgar minds, are those in which
you obtain such premisses as will enable you to draw your final
conclusion without asking any farther concessions. But this will
rarely happen. Even after you have obtained all the premisses
substantially necessary to your final conclusion, you will generally
be forced to draw out two or more prosyllogisms or preliminary
syllogisms, and to ask the assent of the respondent to these, before
you can venture to enunciate the final conclusion. This second grade
of evidence is however sufficient, even if the premisses fall short
of the highest probability.[436]
[Footnote 436: Topic. VIII. xii. p. 162, a. 35-b. 2.]
On the other hand, your argument may deserve to be pronounced false
on four distinct grounds:--(1) If your syllogism appears to prove the
conclusion but does not really prove it, being then an _eristic_ or
_contentious_ syllogism; (2) If the conclusion be good but not
**relevant to the thesis, which is most likely to happen
where you employ _Reductio ad Impossible_; (3) If your conclusion
though valid and even relevant, is not founded on the premisses and
_principia_ appropriate to the thesis; (4) If your premisses are
false, even though the conclusion in itself may prove true, since it
has already been said that a true conclusion may sometimes be
obtained from false premisses.[437]
[Footnote 437: Ibid. b. 3-15: [Greek: pseudê\s de\ lo/gos kalei=tai
tetrachô=s], &c.]
Falsehood in your argument will be rather your own fault than that of
your argument, especially if you yourself are not aware of its
falsehood. Indeed, there are some false arguments which are more
valuable in Dialectic than many true ones; where, for example, from
highly probable premisses you refute some recognized truth. Such an
argument is sure to serve as a demonstration of other truths; at the
very least, it shows that some one of the propositions concerned is
altogether untrue.[438] On the other hand, if you prove a true
conclusion by premisses false and improbable, your argument will be
more worthless than many others in which the conclusion is false;
from such premisses, indeed, the conclusion may well be really
false.[439]
[Footnote 438: Ibid. b. 16-22: [Greek: to\ me\n ou)=n pseudê= to\n
lo/gon ei)=nai tou= le/gontos a(ma/rtêma ma=llon ê)\ tou= lo/gou,
kai\ ou)de\ tou= le/gontos a)ei\ to\ a(ma/rtêma, a)ll' o(/tan
lantha/nê| au)to/n, e)pei\ kath' au(to/n _ge pollô=n a)lêthô=n
a)podecho/metha ma=llon, a)\n e)x o(/ti ma/lista dokou/ntôn a)nairê=|
ti tô=n a)lêthô=n; toiou=tos ga\r ô)\n e(te/rôn a)lêthô=n
a)po/deixi/s e)stin_; dei= ga\r tô=n keime/nôn ti mê\ ei)=nai
pantelô=s, ô(/st' e)/stai _tou/tou_ a)po/deixis.]]
[Footnote 439: Ibid. b. 22-24.]
In estimating the dialectical value of an argument, therefore, we
must first look whether the conclusion is formally valid; next,
whether the conclusion is true or false; lastly, what are the
premisses from whence it is derived.[440] For, if it be derived from
premisses false yet probable, it has logical or dialectical value;
while, if derived from premisses true yet improbable, it has
none.[441] If derived from premisses both false and improbable, it
will of course be worthless; either absolutely in itself, or with
reference to the thesis under debate.
[Footnote 440: Ibid. b. 24: [Greek: ô(/ste dê=lon o(/ti prô/tê me\n
e)pi/skepsis lo/gou kath' au(to\n ei) sumperai/netai, deute/ra de\
po/teron a)lêthe\s ê)\ pseu=dos; tri/tê d' e)k poi/ôn tinô=n.]]
[Footnote 441: Topic. VIII. xii. p. 162, b. 27: [Greek: ei) me\n ga\r
e)k pseudô=n e)ndo/xôn de/, logiko/s, ei) d' e)x o)/ntôn me\n
a)do/xôn de/, phau=los], &c.]
Two faults of questioners in Dialectic are dealt with specially by
Aristotle:--(1) _Petitio Principii_; (2) _Petitio Contrariorum_. He
had touched upon both of them (in the Analytica Priora) as they
concerned the demonstrative process, or the proving of truth: he now
deals with them as they concern the dialectical process, or the
setting out of opinions and probabilities.[442]
[Footnote 442: Ibid. xiii. p. 162, b. 31: [Greek: to\ d' e)n a)rchê=|
kai\ ta\ e)nanti/a pô=s ai)tei=tai o( e)rôtô=n, _kat' a)lê/theian_
me\n e)n toi=s A)nalutikoi=s] (Priora, II. xvi.) [Greek: ei)/rêtai,
_kata\ do/xan_ de\ nu=n lekte/on.]]
Five distinct modes may be enumerated of committing the fault called
_Petitio Principii_:--
1. You may put as a question the very conclusion which it is
incumbent on you to prove, in refutation of the thesis of the
respondent. If this is done in explicit terms, your opponent can
hardly fail to perceive it; but he possibly may fail, if you
substitute an equivalent term or the definition in place of the
term.[443]
[Footnote 443: Ibid. b. 34. [Greek: prô=ton ei)/ tis au)to\ to\
dei/knusthai de/on ai)tê/sei; tou=to d' e)p' au)tou= me\n ou)
r(a/|dion lantha/nein, e)n de\ toi=s sunônu/mois, kai\ e)n o(/sois
to\ o)/noma kai\ o( lo/gos to\ au)to\ sêmai/nei, ma=llon.]]
2. If the conclusion which you are seeking to prove is a particular
one, you may put as a question the universal in which it is
comprised. Thus, if you are to prove that the knowledge of Contraries
is one and the same, you may put as a question, Is not the knowledge