Aristotle
the proposition in debate is not perfectly relevant to the thesis,
but merely has the semblance of being so. It is neither really nor
apparently necessary, when there does not exist even this semblance
of relevance, and when some other way is open of bringing
bye-confutation to bear on the respondent. You ought to avoid
entirely such a procedure in this last class of cases; for it is an
abuse of the genuine purpose of Dialectic. If you do resort to it,
the respondent should grant your interrogations, but at the same time
notify that they are irrelevant to the thesis. Such notification will
render his concessions rather troublesome than advantageous for your
purpose.[101]
[Footnote 100: Ibid. v. p. 111, b. 32-p. 112, a. 2: [Greek: e)/ti o(
sophistiko\s tro/pos, to\ a)/gein ei)s toiou=ton pro\s o(\
eu)porê/somen e)picheirêma/tôn], &c.]
[Footnote 101: Ibid. p. 112, a. 2-15. [Greek: dei= d' eu)labei=sthai
to\n e)/schaton tô=n r(êthe/ntôn tro/pôn; pantelô=s ga\r
a)pêrtême/nos kai\ a)llo/trios e)/oiken ei)=nai tê=s dialektikê=s.]
The epithet [Greek: sophistiko\s tro/pos] is probably intended by
Aristotle to apply only to this last class of cases.
This paragraph is very obscure, and is not much elucidated by the
long Scholion of Alexander (pp. 267-268, Br.).]
10. You will recollect that every proposition laid down or granted by
the respondent carries with it by implication many other
propositions; since every affirmation has necessary consequences,
more or fewer. Whoever says that Sokrates is a man, has said also
that he is an animal, that he is a living creature, biped, capable of
acquiring knowledge. If you can disprove any of these necessary
consequences, you will have disproved the thesis itself. You must
take care, however, that you fix upon some one of the consequences
which is really easier, and not more difficult, to refute than the
thesis itself.[102]
[Footnote 102: Topic. II. v. p. 112, a. 16-23.]
11. Perhaps the thesis set up by the respondent may be of such a
nature that one or other of two contrary predicates must belong to
the subject; _e.g._, either health or sickness. In that case, if you
are provided with arguments bearing on one of the two contraries, the
same arguments will also serve indirectly for proof, or for disproof,
of the other. Thus, if you show that one of the two contraries does
belong to the subject, the same arguments prove that the other does
not; _vice versâ_, if you show that one of them does not belong, it
follows that the other does.[103]
[Footnote 103: Topic. II. vi. p. 112, a. 25-31. [Greek: dê=lon ou)=n
o(/ti pro\s a)mphô chrê/simos o( to/pos.]]
12. You may find it advantageous, in attacking the thesis, to
construe the terms in their strict etymological sense, rather than in
the sense which common **usage gives them.[104]
[Footnote 104: Ibid. a. 32-38: [Greek: e)/ti to\ e)picheirei=n
metaphe/ronta tou)/noma e)pi\ to\n lo/gon, ô(s ma/lista prosê=kon
e)klamba/nein ê)\ ô(s kei=tai tou)/noma.]
The illustrative examples which follow prove that [Greek: lo/gon]
here means the etymological origin, and not the definition, which is
its more usual meaning.]
13. The predicate may belong to its subject either necessarily, or
usually, or by pure hazard. You will take notice in which of these
three ways the respondent affirms it, and whether that which he
chooses is conformable to the fact. If he affirms it as necessary,
when it is really either usual or casual, the thesis will be open to
your attacks. If he affirms it without clearly distinguishing in
which of the three senses he intends it to be understood, you are at
liberty to construe it in that one of the three senses which best
suits your argument.[105]
[Footnote 105: Ibid. b. 1-20. This _locus_ seems unsuitable in that
part of the Topica where Aristotle professes to deal with theses
[Greek: tou= symbebêko/tos], or theses affirming or denying
_accidental_ predicates. It is one of the suppositions here that the
respondent affirms the predicate as _necessary_.]
14. Perhaps the thesis may have predicate and subject exactly
synonymous, so that the same thing will be affirmed as an accident of
itself. On this ground it will be assailable.[106]
[Footnote 106: Ibid. b. 21-26.]
15. Sometimes the thesis will have more than one proposition contrary
to it. If so, you may employ in arguing against it that one among its
various contraries which is most convenient for your purpose.[107]
Perhaps the predicate (accidental) of the thesis may have some
contrary: if it has, you will examine whether that contrary belongs
to the subject of the thesis; and, should such be the case, you may
use it as an argument to refute the thesis itself.[108] Or the
predicate of the thesis may be such that, if the thesis be granted,
it will follow as a necessary consequence that contrary predicates
must belong to the same subject. Thus, if the thesis be that the
Platonic Ideas exist _in us_, it follows necessarily that they are
both in motion and at rest; both perceivable by sense, and cogitable
by intellect.[109] As these two predicates (those constituting the
first pair as well as the second pair) are contrary to each other,
and cannot both belong to the same subject, this may be used as an
argument against the thesis from which such consequence follows.
[Footnote 107: Ibid. vii. p. 112, b. 28-p. 113, a. 19. [Greek: dê=lon
ou)=n e)k tô=n ei)rême/nôn o(/ti tô=| au)tô=| plei/ona e)nanti/a
sumbai/nei gi/nesthai.--lamba/nein ou)=n tô=n e)nanti/ôn o(po/teron
a)\n ê)=| pro\s tê\n the/sin chrê/simon.]]
[Footnote 108: Ibid. viii. p. 113, a. 20-23.]
[Footnote 109: Topic. II. viii. p. 113, a. 24-32: [Greek: ê)\ ei)/ ti
toiou=ton ei)/rêtai kata/ tinos, ou(= o)/ntos a)na/gkê ta\ e)nanti/a
u(pa/rchein; oi(=on ei) ta\s i)de/as e)n ê(mi=n e)/phêsen ei)=nai;
kinei=sthai/ te ga\r kai\ ê)remei=n au)ta\s sumbê/setai, e)/ti de\
ai)sthêta\s kai\ noêta\s ei)=nai.] Aristotle then proceeds to state
how this consequence arises. Those who affirm the Platonic Ideas,
assign to them as fundamental characteristic, that they are at rest
and cogitable. But, if the Ideas exist _in us_, they must be
moveable, because _we_ are moved; they must also be perceivable by
sense, because it is through vision only that we discriminate and
know differences of form. Waitz observes (in regard to the last pair,
[Greek: kai\ ai)sthêtai/]): "Nam singulæ ideæ certam quandam rerum
speciem et formam exprimunt: species autem et forma oculis cernitur."
I do not clearly see, however, that this is a consequence of
affirming Ideas to be [Greek: e)n ê(mi=n]; it is equally true if they
are _not_ [Greek: e)n ê(mi=n].]
16. We know that whatever is the recipient of one of two contraries,
is capable also of becoming recipient of the other. If, therefore,
the predicate of the thesis has any contrary, you will examine
whether the subject of the thesis is capable of receiving such
contrary. If not, you have an argument against the thesis. Let the
thesis be, The appetitive principle is ignorant. If this be true,
that principle must be capable of knowledge.[110] Since this last is
not generally admitted, you have an argument against the thesis.
[Footnote 110: Topic. II. vii. p. 113, a. 33-b. 10.]
17. We recognize four varieties of _Opposita_: (1) Contradictory; (2)
Contrary; (3) _Habitus_ and _Privatio_; (4) _Relata_. You will
consider how the relation in each of these four varieties bears upon
the thesis in debate.
In regard to Contradictories, you are entitled, converting the terms
of the thesis, to deny the predicate of the converted proposition
respecting the negation of the subject. Thus, if man is an animal,
you are entitled to infer, What is not an animal is not a man. You
will prove this to be an universal rule by Induction; that is, by
citing a multitude of particular cases in which it is indisputably
true, without possibility of finding any one case in which it does
not apply. If you can prove or disprove the converted obverse of the
thesis--What is not an animal is not a man--you will have proved or
disproved, the thesis itself, Man is an animal. This _locus_ is
available both for assailant and respondent.[111]
[Footnote 111: Ibid. viii. p. 113, b. 15-26: [Greek: e)pei\ d' ai(
a)ntithe/sis te/ssares, skopei=n e)k me\n tô=n a)ntipha/seôn e)k tê=s
a)kolouthê/seôs kai\ a)nairou=nti kai\ kataskeua/zonti; _lamba/nein
d' e)x e)pagôgê=s_, oi(=on ei) o( a)/nthrôpos zô=|on, to\ mê\ zô=|on
ou)k a)/nthrôpos; _o(moi/ôs de\ kai\ e)pi\ tô=n a)/llôn--e)pi\
pa/ntôn ou)=n to\ toiou=ton a)xiôte/on_.]
Aristotle's declaration, that this great logical rule can only be
proved by Induction, deserves notice. I have remarked the same thing
about his rules for the conversion of propositions, in the beginning
of the Analytica Priora. See above, p. 145, seq.]
In regard to Contraries, you will study the thesis, to see whether
the contrary of the predicate can be truly affirmed respecting the
contrary of the subject, or whether the contrary of the subject can
be truly affirmed respecting the contrary of the predicate. This last
alternative occurs sometimes, but not often; in general the first
alternative is found to be true. You must make good your point here
also by Induction, or by repetition of particular examples. This
_locus_ will serve either for the purpose of refutation or for that
of defence, according to circumstances. If neither of the two
alternatives above-mentioned is found correct, this is an argument
against the thesis.[112]
[Footnote 112: Topic. II. viii. p. 113, b. 27-p. 114, a. 6. [Greek:
lamba/nein de\ kai\ ta\ toiau=ta e)x e)pagôgê=s, e)ph' o(/son
chrê/simon.--spa/nion de\ to\ a)na/palin e)pi\ tô=n e)nanti/ôn
sumbai/nei, a)lla\ toi=s plei/stois e)pi\ tau)ta ê( a)kolou/thêsis.
ei) ou)=n mêt' e)pi\ tau)ta\ tô=| e)nanti/ô| to\ e)nanti/on
a)kolouthei= mê/te a)na/palin, dê=lon o(/ti ou)de\ tô=n r(êthe/ntôn
a)kolouthei= to\ e(/teron tô=| e(te/rô|.]]
In regard to _Habitus_ and _Privatio_, the rule is the same as about
Contraries; only that the first of the two above alternatives always
holds, and the second never occurs.[113] If sensible perception can
be predicated of vision, insensibility also can be predicated of
blindness; otherwise, the thesis fails.
[Footnote 113: Ibid. p. 114, a. 7-12.]
In regard to _Relata_, the inference holds from the correlate of the
subject to the correlate of the predicate. If knowledge is belief,
that which is known is believed; if vision is sensible perception,
that which is visible is sensibly perceivable. Some say that there
are cases in which the above does not hold; _e.g._, That which is
sensibly perceivable is knowable; yet sensible perception is not
knowledge. But this objection is not valid; for many persons dispute
the first of the two propositions. This _locus_ will be equally
available for the purpose of refutation--thus, you may argue--That
which is sensibly perceivable is not knowable, because sensible
perception is not knowledge.[114]
[Footnote 114: Ibid. a. 13-25.]
18. You will look at the terms of the proposition, also, in regard to
their Derivatives, Inflections, &c., and to matters associated with
them in the way of production, preservation, &c. This _locus_ serves
both for proof and for refutation. What is affirmable of the subject,
is affirmable also of its derivatives: what is not affirmable of the
derivatives, is not affirmable of the subject itself.[115]
[Footnote 115: Ibid. ix. p. 114, a. 26-b. 5. [Greek: du/stoicha,
ptô/seis, ta\ poiêtika\ kai\ phulaktika/--dê=lon ou)=n o(/ti e(no\s
o(poiouou=n deichthe/ntos tô=n kata\ tê\n au)tê\n sustoichi/an
a)gathou= ê)\ e)painetou=, kai\ ta\ loipa\ pa/nta dedeigme/na
gi/netai.]--b. 23: [Greek: ô(=n me\n ga\r ta\ poiêtika\ a)gatha/,