Editing Chrysippus (section)

===Propositions===
Chrysippus defined a proposition as "that which is capable of being denied or affirmed as it is in itself" and gave examples of propositions such as "it is day" and "Dion is walking."<ref>Diogenes Laërtius, vii. 65</ref><ref>{{harvnb|Gould|1970|pp=69–70}}</ref> He distinguished between simple and non-simple propositions, which in modern terminology are known as [[Atomic sentence|atomic]] and [[Molecular sentence|molecular]] propositions.<ref name="johansen466"/> A simple proposition is an elementary statement such as "it is day."<ref name="gould71">{{harvnb|Gould|1970|p=71}}</ref> Simple propositions are linked together to form non-simple propositions by the use of [[logical connective]]s. Chrysippus enumerated five kinds of molecular propositions according to the connective used:<ref name="gould71"/>

{| class="wikitable" style="margin:1.0em auto;border:1px;background:white;"
!colspan=2 style="background:white;text-align:center;"| Logical connectives
|- style="background:white"
! Type                !! Example
|-
| if            || '''if''' it is day, it is light
|-
| and           || it is day '''and''' it is light
|-
| either ... or || '''either''' it is day '''or''' it is night
|-
| because       || '''because''' it is day, it is light
|-
| | more/less likely ... than || '''more likely''' it is day '''than''' it is night
|}

Thus several types of molecular propositions, familiar to modern logic, were listed by Chrysippus, including the [[Logical conjunction|conjunction]], the [[Logical disjunction|disjunction]], and the [[Material conditional|conditional]],<ref name="johansen467">{{harvnb|Johansen|Rosenmeier|1998|p=467}}</ref> and Chrysippus studied their criteria of [[Logical truth|truth]] closely.<ref name="johansen467"/>