The Complete Aristotle (eng.)

junction of leaf-stalk and stem which
defines deciduous.
    If an explanation in formal terms of the inter-relation of cause
and effect is demanded, we shall offer the following. Let A be an
attribute of all B, and B of every species of D, but so that both A
and B are wider than their respective subjects. Then B will be a
universal attribute of each species of D (since I call such an
attribute universal even if it is not commensurate, and I call an
attribute primary universal if it is commensurate, not with each
species severally but with their totality), and it extends beyond
each of them taken separately.
    Thus, B is the cause of A’s inherence in the species of D:
consequently A must be of wider extent than B; otherwise why should
B be the cause of A’s inherence in D any more than A the cause of
B’s inherence in D? Now if A is an attribute of all the species of
E, all the species of E will be united by possessing some common
cause other than B: otherwise how shall we be able to say that A is
predicable of all of which E is predicable, while E is not
predicable of all of which A can be predicated? I mean how can
there fail to be some special cause of A’s inherence in E, as there
was of A’s inherence in all the species of D? Then are the species
of E, too, united by possessing some common cause? This cause we
must look for. Let us call it C.
    We conclude, then, that the same effect may have more than one
cause, but not in subjects specifically identical. For instance,
the cause of longevity in quadrupeds is lack of bile, in birds a
dry constitution-or certainly something different.
18
    If immediate premisses are not reached at once, and there is not
merely one middle but several middles, i.e. several causes; is the
cause of the property’s inherence in the several species the middle
which is proximate to the primary universal, or the middle which is
proximate to the species? Clearly the cause is that nearest to each
species severally in which it is manifested, for that is the cause
of the subject’s falling under the universal. To illustrate
formally: C is the cause of B’s inherence in D; hence C is the
cause of A’s inherence in D, B of A’s inherence in C, while the
cause of A’s inherence in B is B itself.
19
    As regards syllogism and demonstration, the definition of, and
the conditions required to produce each of them, are now clear, and
with that also the definition of, and the conditions required to
produce, demonstrative knowledge, since it is the same as
demonstration. As to the basic premisses, how they become known and
what is the developed state of knowledge of them is made clear by
raising some preliminary problems.
    We have already said that scientific knowledge through
demonstration is impossible unless a man knows the primary
immediate premisses. But there are questions which might be raised
in respect of the apprehension of these immediate premisses: one
might not only ask whether it is of the same kind as the
apprehension of the conclusions, but also whether there is or is
not scientific knowledge of both; or scientific knowledge of the
latter, and of the former a different kind of knowledge; and,
further, whether the developed states of knowledge are not innate
but come to be in us, or are innate but at first unnoticed. Now it
is strange if we possess them from birth; for it means that we
possess apprehensions more accurate than demonstration and fail to
notice them. If on the other hand we acquire them and do not
previously possess them, how could we apprehend and learn without a
basis of pre-existent knowledge? For that is impossible, as we used
to find in the case of demonstration. So it emerges that neither
can we possess them from birth, nor can they come to be in us if we
are without knowledge of them to the extent of having no such
developed state at all. Therefore we must possess a capacity of
some sort, but not such as to rank higher in accuracy than these
developed states. And this at least is an obvious characteristic of
all animals, for they possess a congenital discriminative capacity
which is called sense-perception. But though sense-perception is
innate in all animals, in some the sense-impression comes to
persist, in others it does not. So animals in which this
persistence does not come to be have either no knowledge at all
outside the act of perceiving, or no knowledge of objects of which
no impression persists; animals in which it does come into being
have perception