In The Coherence of Theism (original:1977, revised ed.:1993), Richard Swinburne argues that the sentence “God exists” is a meaningful indicative sentence that expresses a coherent proposition. He does this by raising objections to arguments that have been given against this view, and by also making a detailed positive case.
For the negative or defensive case, Swinburne starts out by raising objections to some general arguments against this view, and later in the book he raises objections to more specific arguments that focus on the alleged incoherence of specific characteristics or combinations of specific characteristics that are used to define the word “God”.
The main general argument against his position that is examined by Swinburne is a logical positivist argument about the sentence “God exists”, derived primarily from A.J. Ayer’s book Language, Truth, and Logic (1936).
This is how Swinburne interprets the skeptical argument presented by Ayer:
(1) If the sentence “God exists” expresses a coherent statement, then the sentence “God exists” expresses either an analytic proposition or else it expresses a synthetic proposition.
(2) The sentence “God exists” does not express an analytic proposition.
(3) The sentence “God exists” does not express a synthetic proposition.
(4) It is not the case that “God exists” expresses a coherent statement.
The logic of this argument is fine, and Swinburne accepts premises (1) and (2), so his focus is on the question of whether premise (3) is true or well-supported.
This skeptical argument is basically a modern version of Hume’s fork. Hume divided claims into two categories: (a) relations of ideas and (b) matters of fact. Hume argued that all claims fall into one or the other category, so since metaphysical sentences do not express either “the relations of ideas” or “matters of fact”, such sentences do not express claims or propositions.
The concept of an analytic proposition can be viewed as a clarification of Hume’s notion of statements that express “the relations of ideas”. The concept of a synthetic proposition can be viewed as a refinement of Hume’s notion of statements that express “matters of fact”. Given the assumption that all coherent propositions can be categorized as either being an analytic or a synthetic proposition, a dilemma simliar to Hume’s fork can be constructed for the sentence “God exists”.