About the Qualifier Habitable 7. This debate is not about the existence of God. Rather this debate defers that question and asks instead whether there can be a foundation for ethics devoid of supernatural support. In other words, the burden is on secularists to put forth an affirmative philosophy. The line between questioning secular ethics and questioning the existence of God is admittedly thin, but there is a line.
Philosophical skepticism is self-refuting and therefore inadmissible.
It does not add to the conversation to claim to know that there is no knowing or to claim to have knowledge that there is no knowledge. It must be, in other words, objectively true. A foundation for ethics must be able to resolve disputes, and a foundation which is true only sometimes, for some people, in some places cannot hope to resolve disputes except by accident. A subjective foundation would not be, in a word, habitable. Ten Philosophical Mistakes by Mortimer J. Adler.