Yeah. In logic it is usually assumed that sentences are atomic when they do not contain logical connectives like “and”. And formal (Montaigne style) semantics makes this more precise, since logic may be hidden in linguistic form. But of course humans don’t start out with language. We have some sort of mental activity, which we somehow synthesize into language, and similar thoughts/propositions can be expressed alternatively with an atomic or a complex sentence. So atomic sentences seem definable, but not abstract atomic propositions as object of belief and desire.
Yeah. In logic it is usually assumed that sentences are atomic when they do not contain logical connectives like “and”. And formal (Montaigne style) semantics makes this more precise, since logic may be hidden in linguistic form. But of course humans don’t start out with language. We have some sort of mental activity, which we somehow synthesize into language, and similar thoughts/propositions can be expressed alternatively with an atomic or a complex sentence. So atomic sentences seem definable, but not abstract atomic propositions as object of belief and desire.