Logic and Theory of Knowledge 125
he placed that "grasp" which I just mentioned and said it was neither
right nor wrong but that it alone deserved to be believed. Therefore, he
said the senses too were reliable because, as I said above, he thought that
a grasp made by the senses was true and reliable, not because it grasped
everything about the object but because it left out nothing [about it]
which could be grasped and because nature had provided this grasp as
a standard for knowledge and a basis for understanding nature itself.
From such [perceptual grasps] conceptions of things are subsequently
impressed on the soul, and these provide not just the foundations but
also certain broader paths leading to the discovery of reason. Error,
however, and rashness and ignorance and opinion and conjecture-in a
word, all that is hostile to a solid and stable assent-all these he banned
from the sphere of wisdom and virtue. On these points rests all of Zeno's
departure from and disagreement with his predecessors.
Cicero Academica 2.24-26 [11-5]
24 .... And, moreover, this point is obvious, that there must be a
principle which wisdom follows when it begins to do something and this
principle must be according to nature. For otherwise impulse (for that
is the translation we use for horme), by which we are driven to act and
pursue what is presented, cannot be stimulated. 25. But that which
stimulates must first be presented [to the agent] and it must be believed;
and this cannot happen if what is presented cannot be distinguished from
what is false. For how can the mind be moved to an impulse if there is
no judgement as to whether what is presented is according to nature or
contrary to it? Similarly, if the mind does not realize what is appropriate
to it, it will never do anything at all, will never be driven to anything,
will never be stimulated. But if it is ever to be moved, what occurs to
the agent must be presented as being true.- And what of the fact that, if the sceptics are right, all reason is
abolished, which is like the light and illumination of life? Will you persist
in that kind of perversity? For reason provides a starting point for inquiry,
which perfects virtue when reason itself has been strengthened by inquir-
ing. And inquiry is an impulse to knowledge and discovery is the goal
of inquiry. But no one discovers what is false, nor can matters which
remain uncertain be discovered; but when things which were previously
veiled are revealed, then they are said to be discovered, and thus both
the starting point of inquiry and the conclusion of perception and under-
standing are obtained by the mind. A demonstration (the Greek is apo-
deixis) is defined thus: "an argument which leads from things perceived
to that which previously was not perceived."