Elliot Temple replied:

Argument 1 -- Existence:

Existence is determined by whether something factors into a non-refuted explanation. E.g. apple trees exist and are an important part of the explanation of where the apples at the grocery store come from. Claiming apple trees don't exist would ruin an existing explanation and leave us confused. Also there's no criticism of apple trees existing. The combination here of there being a purpose to believing something exists (explains sightings of apple trees, explains how apples are produced, etc) and also no criticism of claiming it exists is adequate to say it exists.

Existence is covered in more detail in DD's books.  http://beginningofinfinity.com/books

God and FSM are not involved in any current non-refuted explanations. So saying they don't exist would not cause any problems.

And there are criticisms of them. The criticism depends on the particular variation (there's many different God claims). Some God claims are vague. Others contradict science.

Regarding free will (the claim that people make choices -- not some magical religious version), it factors into various important explanations in moral philosophy. When someone says "don't murder people", what's the point if there's no free will? It's trying to talk about what choices to make (choose not to murder rather than choose to murder) which refers to free will. If you deny free will, moralizing about e.g. murder no longer makes sense, so you're ruining important existing knowledge. In order to make a good case against free will, one would have to either basically refute morality as being a load of crap, or else come up with a new way to make sense of morality without free will. Without that, at best you could hope to argue for a situation of confusion and not knowing the answer. In general the arguments against free will people give don't have anything to do with the case for it I make (about it factoring into important explanations).

Argument 2 -- Purpose:

Ideas need to have a purpose to be any good. That is, they should solve some kind of problem of some sort. Without that, there's no way to even tell if the idea succeeds. So before a God or FSM claim can be evaluated, the proposer needs to say the purpose of it (what problem it solves). Without that, the idea is incomplete and therefore bad and refuted. (The purpose of an idea is often unstated but implied. Sometimes that works, but when there's a disagreement then stating it clearly is often a good idea. Here, stating it clearly is needed.)

Free will has a purpose. Discussion of choices is integral to moral philosophy. Moral philosophy helps people live better lives.

Tangent -- Proof:

The goal of thinking isn't to infallibly prove or disprove things. It's to learn more an more in an open-ended, unbounded process of creating knowledge, solving problems, understanding the truth better, etc. So what we generally look for is refutation (is an idea criticized?) rather than proof (do we know a final answer that could never ever be reconsidered no matter what?). A refutation needs to stand against all counter-criticism and current knowledge to be accepted. But it doesn't have to stand against all future innovation, we may change our mind about it later, and that's OK and doesn't take away its value now.

See this post in its original context:  https://groups.yahoo.com/neo/groups/fallible-ideas/conversations/messages/19324

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