A.J Ayer

• What was he known as?

  A logical positivist.
• What did he say?

  Talk of God must be nonsensical since the "notion of a person whose essential attributes is not an intelligible notion at all." Just because a word exists, does not mean there is a correspondence in reality.
• What is a strong version?


  When there is no doubt that a statement is true- verifiable using sense experience
• What is a weak version?


  There are some observations relevant to proving an assertion true/false. Verifiable in principle is sufficient to be able to know how to verify it.