Who throws the dice for you?

[Jackalope]

'Only if' and 'if & only if' = 'because'. How's this for an example:
- If there's one possible reason, it's not an 'if'
- Only if there's one possible reason is it not an 'if'
See how the construction of the second statement makes it an assumption?

This http://math.stackexchange.com/questions/...if-and-iff appears to support your position. I withdraw my argument.