Editing Zeno of Citium (section)

===Logic===
In his treatment of logic, Zeno was influenced by [[Stilpo]] and the other [[Megarian school of philosophy|Megarians]]. Zeno urged the need to lay down a basis for logic because the wise person must know how to avoid deception.<ref>Cicero, ''Academica'', ii. 20.</ref> [[Cicero]] accused Zeno of being inferior to his philosophical predecessors in his treatment of logic,<ref>Cicero, ''de Finibus'', iv. 4.</ref> and it seems true that a more exact treatment of the subject was laid down by his successors, including [[Chrysippus]].<ref>Sextus Empiricus, ''adv. Math.'' vii. 253.</ref> Zeno divided true conceptions into the comprehensible and the incomprehensible,<ref>Cicero, ''Academica'', ii. 6, 24.</ref> permitting for free-will the power of assent (''sinkatathesis''/συνκατάθεσις) in distinguishing between sense impressions.<ref name="cicero1">Cicero, ''Academica'', i. 11.</ref> Zeno said that there were four stages in the process leading to true [[knowledge]], which he illustrated with the example of the flat, extended hand, and the gradual closing of the fist:
<blockquote>Zeno stretched out his fingers, and showed the palm of his hand, – "Perception," – he said, – "is a thing like this."– 
Then, when he had closed his fingers a little, – "Assent is like this." – Afterwards, when he had completely closed his hand, and showed his fist, that, he said, was Comprehension. From which simile he also gave that state a new name, calling it ''[[katalepsis]]'' (κατάληψις). But when he brought his left hand against his right, and with it took a firm and tight hold of his fist: – "Knowledge" – he said, was of that character; and that was what none but a wise person possessed.<ref>Cicero, ''Academica'', 2.145 [47]</ref></blockquote>