Who throws the dice for you?

[Angrboda]

I don't agree. It's equivalent to "weird things happen if-and-only-if god exists", and I fail to see the distinction between that and 'weird things happen if god exists".

'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?

I think you're over-interpreting things. To me, your two statements imply different sets of entailments, but neither is a synonym for "because." I think you're substituting a causal notion for a logical one.

- If a pie is tasty to me, then I like that pie.
- Only if a pie is tasty to me, then I like that pie.

There may be other reasons that I like that pie (perhaps its color). The first sentence implies a sufficient condition for me to like that pie, but it doesn't state that the condition is a necessary pre-condition for my liking that pie. The second specifies a condition that is both sufficient and necessary for me to like that pie. Neither states that I like that pie "because" it is tasty to me. (Although that might be a valid inference, it might not; I might just happen to find all pies of a certain color tasty, purely coincidentally, and it's the color I like, not the taste.)

In other words:
B, if A means A -> B; B, only if A means ((A->B) and (B->A)), logically. It says nothing about cause, nor does it imply anything about the truth values of A or B, and it doesn't assume A.

Anyway. Obviously still not seeing it.

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A better, less contrived example involves drownings, air temperature, and ice cream sales. It's known that the frequency of drownings rises along with rises in ice cream sales. This is because most drownings occur during swimming season which coincides with warmer temperatures because people go swimming more often when it's warm. The correlation with ice cream sales is a confounding variable. Nonetheless, the following is true:

1. Frequency of drownings is high only if volume of ice cream sales is high.

The rest of his original syllogism remains:
1. Frequency of drownings is high only if volume of ice cream sales is high.
2. Volume of ice cream sales is high.
Conclusion: Frequency of drownings is high.

This is a valid syllogism, its premises are sound, there is no begging the question, and the "only if" in premise one does not mean "because." Am I missing something?