Aristotle
[Footnote 29: Ibid. xi. p. 104, b. 24-28: [Greek: ê)\ peri\ ô(=n
lo/gon e)/chomen e)nanti/on tai=s do/xais--tou=to ga/r, ei) kai/ tini
mê\ dokei=, do/xeien a)\n dia\ to\ lo/gon e)/chein.]]
These conditions apply both to problems propounded for debate, and to
premisses tendered on either side during the discussion. Both the
interrogator and the respondent--the former having to put appropriate
questions, and the latter to make appropriate answers--must know and
keep in mind these varieties of existing opinion among the multitude
as well as among the special dissident authorities above indicated.
The dialectician ought to collect and catalogue such _Endoxa_, with
the opinions analogous to them, out of written treatises and
elsewhere;[30] distributing them under convenient heads, such as
those relating to good and evil generally, and to each special class
of good, &c. Aristotle, however, admonishes him that he is debating
problems not scientifically, but dialectically: having reference not
to truth, but to opinion.[31] If the interrogator were proceeding
scientifically and didactically, he would make use of all true and
ascertained propositions, whether the respondent conceded them or
not, as premisses for his syllogism. But in Dialectic he is dependent
on the concession of the respondent, and can construct his syllogisms
only from premisses that have been conceded to him.[32] Hence he must
keep as closely as he can to opinions carrying extrinsic authority,
as being those which the respondent will hesitate to disallow.[33]
[Footnote 30: Topic. I. xiv. p. 105, b. 1-18. [Greek: e)kle/gein de\
chrê\ kai\ e)k tô=n gegramme/nôn lo/gôn.]]
[Footnote 31: Ibid. b. 30: [Greek: pro\s me\n ou)=n philosophi/an
kat' a)lê/theian peri\ au)tô=n pragmateute/on, dialektikô=s de\ pro\s
do/xan.]]
[Footnote 32: Ibid. VIII. i. p. 155, b. 10: [Greek: pro\s e(/teron
ga\r pa=n to\ toiou=ton, tô=| de\ philoso/phô| kai\ zêtou=nti kath'
e(auto\n ou)de\n me/lei, e)a\n a)lêthê= me\n ê)=| kai\ gnô/rima di'
ô(=n o( sullogismo/s, mê\ thê=| d' au)ta\ o( a)pokrino/menos], &c.]
[Footnote 33: Ibid. i. p. 156, b. 20: [Greek: chrê/simon de\ kai\ to\
e)pile/gein o(/ti su/nêthes kai\ lego/menon to\ toiou=ton; _o)knou=si
ga\r kinei=n to\ ei)ôtho/s_, e)/nstasin mê\ e)/chontes.]]
Moreover, the form of the interrogation admissible in dialectic
debate is peculiar. The respondent is not bound to furnish any
information in his answer: he is bound only to admit, or to deny, a
proposition tendered to him. You must not ask him, What is the genus
of man? You must yourself declare the genus, and ask whether he
admits it, in one or other of the two following forms--(1) Is animal
the genus of man? (2) Is animal the genus of man, or not? to which
the response is an admission or a denial.[34]
[Footnote 34: Ibid. I. iv. p. 101, b. 30. The first of these two
forms Aristotle calls a [Greek: pro/tasis], the second he calls a
[Greek: pro/blêma]. But this distinction between these two words is
not steadily adhered to: it is differently declared in Topic. I. x.,
xi. p. 104, as Alexander has remarked in the Scholia, p. 258, b. 4,
Brand. Compare also De Interpretat. p. 20, b. 26; and Topic. VIII.
ii. p. 158, a. 14: [Greek: ou) dokei= de\ pa=n to\ katho/lou
dialektikê\ pro/tasis ei)=nai, oi(=on ti/ e)stin a)/nthrôpos, ê)\
posachô=s le/getai ta)gatho/n? e)/sti ga\r pro/tasis dialektikê\
pro\s ê(\n e)/stin a)pokri/nasthai nai\ ê)\ ou)/; pro\s de\ ta\s
ei)rême/nas ou)k e)/stin. dio\ ou) dialektika/ e)sti ta\ toiau=ta
tô=n e)rôtêma/tôn, a)\n mê\ au)to\s diori/sas ê)\ dielo/menos
ei)/pê|.]]
Dialectic procedure, both of the assailant and of the defendant, has
to do with propositions and problems; accordingly, Aristotle
introduces a general distribution of propositions under four heads.
The predicate must either be Genus, or Proprium, or Accident, of its
subject. But the Proprium divides itself again into two. It always
reciprocates with, or is co-extensive with, its subject; but
sometimes it declares the essence of the subject, sometimes it does
not. When it declares the essence of the subject, Aristotle calls it
the Definition; when it does not declare the essence of the subject,
although reciprocating therewith, he reserves for it the title of
Proprium. Every proposition, and every problem, the entire material
of Dialectic, will declare one of these four--Proprium, Definition,
Genus, or Accident.[35] The Differentia, as being attached to the
Genus, is ranked along with the Genus.[36]
[Footnote 35: Topic. I. iv. p. 101, b. 17-36.]
[Footnote 36: Ibid. b. 18: [Greek: tê\n diaphora\n ô(s ou)=san
genikê\n o(mou= tô=| ge/nei takte/on.]]
The above four general heads include all the Predicables, which were
distributed by subsequent logicians (from whom Porphyry borrowed)
into five heads instead of four--Genus, Species, Differentia,
Proprium, Accident; the Differentia being ranked as a separate item
in the quintuple distribution, and the Species substituted in place
of the Definition. It is under this quadruple classification that
Aristotle intends to consider propositions and problems as matters
for dialectic procedure: he will give argumentative suggestions
applicable to each of the four successively. It might be practicable
(he thinks) to range all the four under the single head of
Definition; since arguments impugning Genus, Proprium, and Accident,
are all of them good also against Definition. But such a
simplification would be perplexing and unmanageable in regard to
dialectic procedure.[37]
[Footnote 37: Topic. I. vi. p. 102, b. 27-38. [Greek: a)ll' ou) dia\
tou=to mi/an e)pi\ pa/ntôn katho/lou me/thodon zêtête/on; ou)/te ga\r
r(a/|dion eu(rei=n tou=t' e)sti/n, ei)/ th' eu(rethei/ê, pantelô=s
a)saphê\s kai\ du/schrêstos a)\n ei)/ê pro\s tê\n prokeime/nên
pragmatei/an.]]
That the quadruple classification is exhaustive, and that every
proposition or problem falls under one or other of the four heads,
may be shown in two ways. First, by Induction: survey and analyse as
many propositions as you will, all without exception will be found to
belong to one of the four.[38] Secondly, by the following Deductive
proof:--In every proposition the predicate is either co-extensive and
reciprocating with the subject, or it is not. If it does reciprocate,
it either declares the essence of the subject, or it does not: if the
former, it is the Definition; if the latter, it is a Proprium. But,
supposing the predicate not to reciprocate with the subject, it will
either declare something contained in the Definition, or it will not.
If it does contain a part of the Definition, that part must be either
a Genus or a Differentia, since these are the constituents of the
Definition. If it does not contain any such part, it must be an
Accident.[39] Hence it appears that every proposition must belong to
one or other of the four, and that the classification is exhaustive.
[Footnote 38: Ibid. viii. p. 103, b. 3: [Greek: mi/a me\n pi/stis ê(
dia\ tê=s e)pagôgê=s; ei) ga/r tis e)piskopoi/ê e(ka/stên tô=n
prota/seôn kai\ tô=n problêma/tôn, phai/noit' a)\n ê)\ a)po\ tou=
o(/rou ê)\] &c.]
[Footnote 39: Topic. I. **viii. p. 103, b. 6-19:
[Greek: a)/llê de\ pi/stis ê( dia\ sullogismou=].
It will be observed that Aristotle here resolves Definition into
Genus and Differentiæ--[Greek: e)peidê\ o( o(rismo\s e)k ge/nous kai\
diaphorô=n e)sti/n]. Moreover, though he does not recognize Species
as a separate head, yet in his definition of Genus he implies Species
as known--[Greek: ge/nos e)sti\ to\ kata\ pleio/nôn kai\
_diaphero/ntôn tô=| ei)/dei_ e)n tô=| ti/ e)sti katêgorou/menon] (p.
102, a. 31).
It thus appears that the quintuple classification is the real and
logical one; but the quadruple may perhaps be more suitable for the
Topica, with a view to dialectic procedure, since debates turn upon
the attack and defence of a Definition.]
Moreover, each of the four Predicables must fall under one or other
of the ten Categories or Predicaments. If the predicate be either of
Genus or Definition, declaring the essence of the subject, it may
fall under any one of the ten Categories; if of Proprium or Accident,
not declaring essence, it cannot belong to the first Category
([Greek: Ou)si/a]), but must fall under one of the remaining
nine.[40]
[Footnote 40: Ibid. ix. p. 103, b. 20-39.]
The notion of Sameness or Identity occurs so often in dialectic
debate, that Aristotle discriminates its three distinct senses or
grades: (1) _Numero_; (2) _Specie_; (3) _Genere_. Water from the same
spring is only _idem specie_, though the resemblance between two cups
of water from the same spring is far greater than that between water
from different sources. Even _Idem Numero_ has different
significations: sometimes there are complete synonyms; sometimes an
individual is called by its proprium, sometimes by its peculiar
temporary accident.[41]
[Footnote 41: Ibid. vii. p. 103, a. 6-39.]
Having thus classified dialectic propositions, Aristotle proceeds to
the combination of propositions, or dialectic discourse and argument.
This is of two sorts, either Induction or Syllogism; of both which we
have already heard in the Analytica. Induction is declared to be
plainer, more persuasive, nearer to sensible experience, and more
suitable to the many, than Syllogism; while this latter carries
greater compulsion and is more irresistible against professed
disputants.[42] A particular example is given to illustrate what
Induction is. But we remark that though it is always mentioned as an
argumentative procedure important and indispensable, yet neither here
nor elsewhere does Aristotle go into any discriminative analysis of
the conditions under which it is valid, as he does about Syllogism in
the Analytica Priora.
[Footnote 42: Ibid. xii. p. 105, a. 10-19: [Greek: po/sa tô=n lo/gôn
ei)/dê tô=n dialektikô=n], &c.]
What helps are available to give to the dialectician a ready and
abundant command of syllogisms? Four distinct helps may be named:[43]
(1) He must make a large collection of Propositions; (2) He must
study and discriminate the different senses in which the Terms of
these propositions are used; (3) He must detect and note Differences;
(4) He must investigate Resemblances.
[Footnote 43: Topic. I. xiii. p. 105, a. 21: [Greek: ta\ d' o)/rgana,
di' ô(=n eu)porê/somen tô=n sullogismô=n, e)sti\ te/ttara, e(/n me\n
to\ prota/seis labei=n, deu/teron de\ posachô=s e(/kaston le/getai
du/nasthai dielei=n, tri/ton ta\s diaphora\s eu(rei=n, te/tarton de\
ê( tou= o(moi/ou ske/psis.]
The term [Greek: o)/rgana], properly signifying _instruments_,
appears here by a strained metaphor. It means simply _helps_ or
_aids_, as may be seen by comparing Top. VIII. xiv. p. 163, b. 9.
Waitz says truly (Prolegg. ad Analyt. Post. p. 294): "unde fit, ut
[Greek: o)/rgana] dicat quæcunque ad aliquam rem faciendam adiumentum
afferant."]
1. About collecting Propositions, Aristotle has already indicated
that those wanted are such as declare _Endoxa_, and other modes of
thought cognate or **analogous to the _Endoxa_:[44] opinions
of the many, and opinions of any small sections or individuals
carrying authority. All such are to be collected (out of written
treatises as well as from personal enquiry); nor are individual
philosophers (like Empedokles) to be omitted, since a proposition is
likely enough to be conceded when put upon the authority of an
illustrious name.[45] If any proposition is currently admitted as
true in general or in most cases, it must be tendered with confidence
to the respondent as an universal principle; for he will probably
grant it, not being at first aware of the exceptions.[46] All
propositions must be registered in the most general terms possible,