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moods。 And in general we must not forget that it is possible to refute
statements by means of one another； I mean； universal statements by
means of particular； and particular statements by means of
universal： but it is not possible to establish universal statements by
means of particular； though it is possible to establish particular
statements by means of universal。 At the same time it is evident
that it is easier to refute than to establish。
The manner in which every syllogism is produced； the number of the
terms and premisses through which it proceeds； the relation of the
premisses to one another； the character of the problem proved in
each figure； and the number of the figures appropriate to each
problem； all these matters are clear from what has been said。
27
We must now state how we may ourselves always have a supply of
syllogisms in reference to the problem proposed and by what road we
may reach the principles relative to the problem： for perhaps we ought
not only to investigate the construction of syllogisms； but also to
have the power of making them。
Of all the things which exist some are such that they cannot be
predicated of anything else truly and universally； e。g。 Cleon and
Callias； i。e。 the individual and sensible； but other things may be
predicated of them （for each of these is both man and animal）； and
some things are themselves predicated of others； but nothing prior
is predicated of them； and some are predicated of others； and yet
others of them； e。g。 man of Callias and animal of man。 It is clear
then that some things are naturally not stated of anything： for as a
rule each sensible thing is such that it cannot be predicated of
anything； save incidentally： for we sometimes say that that white
object is Socrates； or that that which approaches is Callias。 We shall
explain in another place that there is an upward limit also to the
process of predicating： for the present we must assume this。 Of
these ultimate predicates it is not possible to demonstrate another
predicate； save as a matter of opinion； but these may be predicated of
other things。 Neither can individuals be predicated of other things；
though other things can be predicated of them。 Whatever lies between
these limits can be spoken of in both ways： they may be stated of
others； and others stated of them。 And as a rule arguments and
inquiries are concerned with these things。 We must select the
premisses suitable to each problem in this manner： first we must lay
down the subject and the definitions and the properties of the
thing； next we must lay down those attributes which follow the
thing； and again those which the thing follows； and those which cannot
belong to it。 But those to which it cannot belong need not be
selected； because the negative statement implied above is convertible。
Of the attributes which follow we must distinguish those which fall
within the definition； those which are predicated as properties； and
those which are predicated as accidents； and of the latter those which
apparently and those which really belong。 The larger the supply a
man has of these； the more quickly will he reach a conclusion； and
in proportion as he apprehends those which are truer； the more
cogently will he demonstrate。 But he must select not those which
follow some particular but those which follow the thing as a whole；
e。g。 not what follows a particular man but what follows every man： for
the syllogism proceeds through universal premisses。 If the statement
is indefinite； it is uncertain whether the premiss is universal； but
if the statement is definite； the matter is clear。 Similarly one
must select those attributes which the subject follows as wholes；
for the reason given。 But that which follows one must not suppose to
follow as a whole； e。g。 that every animal follows man or every science
music； but only that it follows； without qualification； and indeed
we state it in a proposition： for the other statement is useless and
impossible； e。g。 that every man is every animal or justice is all
good。 But that which something follows receives the mark 'every'。
Whenever the subject； for which we must obtain the attributes that
follow； is contained by something else； what follows or does not
follow the highest term universally must not be selected in dealing
with the subordinate term （for these attributes have been taken in
dealing with the superior term； for what follows animal also follows
man； and what does not belong to animal does not belong to man）； but
we must choose those attributes which are peculiar to each subject。
For some things are peculiar to the species as distinct from the
genus； for species being distinct there must be attributes peculiar to
each。 Nor must we take as things which the superior term follows；
those things which the inferior term follows； e。g。 take as subjects of
the predicate 'animal' what are really subjects of the predicate
'man'。 It is necessary indeed； if animal follows man； that it should
follow all these also。 But these belong more properly to the choice of
what concerns man。 One must apprehend also normal consequents and
normal antecedents…； for propositions which obtain normally are
established syllogistically from premisses which obtain normally； some
if not all of them having this character of normality。 For the
conclusion of each syllogism resembles its principles。 We must not
however choose attributes which are consequent upon all the terms： for
no syllogism can be made out of such premisses。 The reason why this is
so will be clear in the sequel。
28
If men wish to establish something about some whole； they must
look to the subjects of that which is being established （the
subjects of which it happens to be asserted）； and the attributes which
follow that of which it is to be predicated。 For if any of these
subjects is the same as any of these attributes； the attribute
originally in question must belong to the subject originally in
question。 But if the purpose is to establish not a universal but a
particular proposition； they must look for the terms of which the
terms in question are predicable： for if any of these are identical；
the attribute in question must belong to some of the subject in
question。 Whenever the one term has to belong to none of the other；
one must look to the consequents of the subject； and to those
attributes which cannot possibly be present in the predicate in
question： or conversely to the attributes which cannot possibly be
present in the subject； and to the consequents of the predicate。 If
any members of these groups are identical； one of the terms in
question cannot possibly belong to any of the other。 For sometimes a
syllogism in the first figure results； sometimes a syllogism in the
second。 But if the object is to establish a particular negative
proposition； we must find antecedents of the subject in question and
attributes which cannot possibly belong to the predicate in
question。 If any members of these two groups are identical； it follows
that one of the terms in question does not belong to some of the
other。 Perhaps each of these statements will become clearer in the
following way。 Suppose the consequents of A are designated by B； the
antecedents of A by C； attributes which cannot possibly belong to A by
D。 Suppose again that the attributes of E are designated by F； the
antecedents of E by G； and attributes which cannot be