Ignosticism
Ignosticism is the view that the question of the existence of God is meaningless because it has no verifiable (or testable) consequences and should therefore be ignored. (See scientific method.) The term was coined by Rabbi Sherwin Wine, founder of the Society for Humanistic Judaism. Ignosticism is often considered synonymous with theological noncognitivism.
In the entry under "God" in the Guide to Humanistic Judaism, published by the Society for Humanistic Judaism, ignosticism is defined as "finding the question of God's existence meaningless because it has no verifiable consequences." This use of the term verifiable is consistent with the usage of logical positivism and indicates that the word "God" is meaningless because theism is incoherent. This doesn't have to imply, however, that the idea of God is emotionally or aesthetically meaningless. It is sufficient to say that the idea of God as a being makes no sense.
For most purposes, this view may be considered a form of agnosticism (sometimes referred to as "apathetic agnosticism"), and falls under the general category of nontheism. But it is a particular form. From this approach, the "I don't know" of agnosticism ceases to mean "I don't know if God exists or not" and becomes "I don't know what you're talking about when you talk about God." This underlies the form of the word: ignosticism, indicating an ignorance of what is meant by a claim of God's existence. Until this ignorance is cleared up, the ignostic is justified in ignoring putative arguments for or against.
So, when the word "God" is spoken, the ignostic may seek to determine if something like a child's definition of a god is meant or if a theologian's is intended.
A child's concept generally has a simple and coherent meaning: a big powerful man in the sky responsible for the weather and other such matters. The ignostic is probably atheistic toward this notion, regarding the balance of evidence to deem against it. In taking this view the ignostic is in agreement not only with all atheists but, ironically, with any serious modern theist.
A theologian's concept is more complex and abstract, often involving such concepts as first cause, sustainer, and unmoved mover and claiming such attributes for God as omnipotent, omniscient, and omnibenevolent. To the ignostic these abstractions, taken singly or in combination, cannot be said to be false; rather, they are muddled, self-contradictory, linguistically empty, or perhaps poetic. Hence, one cannot meaningfully expound on the existence or nonexistence of God.
The consistent ignostic, therefore, awaits a coherent definition of God (or of any other metaphysical concept to be discussed) before engaging in arguments for or against.
Historical antecedent
The eighteenth century French philosopher Denis Diderot, when accused of being an atheist, replied that he simply did not care whether God existed or not. In response to Voltaire, he wrote that it is "very important not to mistake hemlock for parsley, but to believe or not to believe in God is not important at all."
There is no evidence of Diderot having directly influenced Rabbi Wine or contemporary ignosticism.