Compatibilism.

Suppose compatibilism about the ability to do otherwise is true and take the butterfly effect to be a correctly expressed consequence of determinism, in conjunction with the fact that if determinism is true, the future entails the past in exactly the same way that the past entails the future, I think we can derive an absurdity.
I'm about to have breakfast and I'm considering from which of two heads of garlic to select a clove, let's suppose that I can choose either. It seems to me to follow from the above assumptions that were I to choose the one that I don't choose, the butterfly effect on the far past would be extremely strong, for example, perhaps it will be the case that if I choose otherwise the dinosaurs wouldn't have become extinct, and there would be no human beings.
Of course the past might not be so conspicuously different if I choose the other head of garlic, but it seems highly likely that the past would be different to such an extent that I wouldn't be alive.