Full Idea
A conditional is called counterfactual because its use seems to presuppose that the user believes its antecedent to be false. Some insist that the antecedent must actually be false.
Clarification
The 'antecedent' is the 'If..' part of the counterfactual claim, not the 'Then..'
Gist of Idea
Counterfactuals presuppose a belief (or a fact) that the condition is false
Source
Thomas Mautner (Penguin Dictionary of Philosophy [1996], p.114)
Book Reference
Mautner,Thomas: 'Dictionary of Philosophy' [Penguin 1997], p.114
A Reaction
I am inclined to favour the stricter second version. "If I am on Earth then I have weight" hardly sounds counterfactual. However, in "If there is a God then I will be saved" it is not clear whether it is counterfactual, so it had better be included.