Full Idea
The connected (proposition) is true when it begins with true and neither could nor can end with false.
Gist of Idea
Conditionals are true when the antecedent is true, and the consequent has to be true
Source
Diodorus Cronus (fragments/reports [c.300 BCE]), quoted by Stephen Mumford - Dispositions 03.4
Book Reference
Mumford,Stephen: 'Dispositions' [OUP 1998], p.45
A Reaction
[Mumford got the quote from Bochenski] This differs from the truth-functional account because it says nothing about when the antecedent is false, which fits in also with the 'supposition' view, where A is presumed. This idea adds necessity.