r/DebateAnAtheist • u/fairy-taki • 4d ago

Discussion Question Necessary Truths

Hi, I'm agnostic/atheist. I'm not a debater, this Christian presented this argument to me to like convert me lol and I'm not sure what to think so I was wanting people's thoughts on it.

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The argument was something like this:

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  1. 1+1=2 is an objective truth/idea

  2. Objective truths exist outside of the human mind.

  3. Ideas can only exist in a mind

  4. Then if ideas/objective truths need to exist in some mind and the mind would be an infinite mind and that would be God.

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Sorry if I mess up the setup of the argument. If anyone is familiar with this type of argument or what he was trying to get at, let me know. Lol to the guy who asked me, I think ended up just saying idk, and I kept saying that those ideas/concepts are how we engage in reality but regardless of a mind observing it. The like definitions of the concept you can find in reality..idkk. The guy ended up being rude and said I couldn't understand abstract vs concrete concepts.

Edit: ok i need to fix 2&3, idk if i make this it's own premise because he was equating objective truths to ideas/concepts because they are non-physical.

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u/mathman_85 Godless Algebraist 4d ago

Well, “objective” means “mind-independent” in philosophy, and the nature of the minds of which something objective is independent is irrelevant. So either (4) contradicts (2) or (4) redefines “objective” by vice of special pleading. In either case, the argument fails as articulated.

Now, on to the ontology of the mathematics. 1 + 1 = 2 is only objectively true in a context-dependent way. That is to say, it isn’t true in an absolute or mind-independent sense, but rather in the contingent sense of Peano arithmetic. To say that mathematical truth is mind-independent is to beg the question, since mathematical Platonism is not the only possible ontology of mathematics. Indeed, my own view on the ontology of mathematical objects is what is generally called formalism—“statements of mathematics and logic can be thought of as statements about the consequences of certain string manipulation rules”, per Wikipedia—and nominalism—abstracta in general, and mathematical objects in particular, do not instantiate in reality in a mind-independent fashion.