The dominant theory of Honest to God is that having rejected the idea of 'God up there', modern secular man needs to recognize that the idea of 'God out there' is also an outdated simplification of the nature of divinity.
Honest to God's core assertion is that by giving up on the concept of a personal god in the sky, modern atheists must accept that the idea of a divine power or energy extending beyond our world is also a outdated and oversimplified representation of the divine essence.