The Trinion Contradictions are a Neo-Deist argument which states that free will, divine intervention (prayer) and destiny are incompatible. It is a great argument that every Deist ought to be familiar with. The Trinion Contradictions go a long way to explaining a Deist worldview to those unfamiliar with it and is a great thought-provoker. However, while I do agree with most of the argument, I do not fully subscribe to the Trinion Contradictions.
Free will, destiny and intervention are three of the most commonly discussed theological topics. The value of the Trinion Contradictions is in demonstrating that some of these are incompatible. It is obvious that free will and destiny are incompatible due to their mutually exclusive nature. If certain events were destined to occur, they would've occurred regardless of what someone may have chosen. For example, if I was destined to eat toast for breakfast this morning, I would not have the free will to choose otherwise. I could not have instead chosen to eat biscuits instead, or to forgo having breakfast at all.
Similarly, destiny and intervention are also mutually exclusive and thus incompatible. Revisiting our breakfast hypothetical, praying to be able to eat anything other than toast would be meaningless if I were destined to eat toast. It might be tougher to apply this concept to things we do not control. Destiny is often invoked for the uncontrollable, such as an accident or a tragic loss. While destiny may be an enticing post hoc rationalization, one can always inevitably trace back the causes for events through natural means. Even if one couldn't, and destiny did exist, praying for circumstances otherwise would be useless.
So what do I disagree with? I think the Trinion Contradictions make an error in deeming free will and intervention to be inherently incompatible. This may seem puzzling, as it seems similar to the mutual exclusivity between free will and destiny. However, it is entirely possible to conceive of certain types of intervention which do not infringe upon free will. Suppose if it were a perfectly sunny day, and God intervened to cause rain. Would this infringe anyone's free will? We could all still choose what we want to do. Certainly, more of us would choose to stay home than go out, but the point remains that such intervention does not violate metaphysical free will.
Of course, I'm not insinuating that every time it rains on a sunny day, it is God intervening. For the sake of the hypothetical, we're assuming ex-ante that it is divine intervention. In the real world, we could not conclusively prove intervention because of epistemic limits. I only wish to demonstrate that the Trinion Contradictions fail to prove why free will and intervention are mutually incompatible.
Obviously, I do not think this falsifies Deism. Just because intervention may exist does not prove the validity of religions. We cannot ever know whether or not intervention has or will occur. There's plenty of wisdom in thinking it doesn't because we would not be able to prove or understand it. I personally think intervention doesn't exist because it is an imperfect means for God to communicate with us, but that is a speculative abductive argument opposed to a logically deductive one. I haven't addressed determinism here, but it is my thesis that free will exists while destiny doesn't. The lesson I would take away from this is that we must be very careful in formulating our thoughts to avoid error. The Deist worldview stands strong in spite of this marginal hiccup.