In “God is a Question, Not an Answer,” William Irwin explains his doubts about anyone who is certain that God exists or that God does not exist. “People who claim certainty about God worry me, both those who believe and those who don’t believe. They do not really listen to the other side of conversations, and they are too ready to impose their views on others. It is impossible to be certain about God.” It’s better to admit that we all live on a “continuum of doubt.”
Socratically Speaking 
I’m not so sure that this is true if the definition of god is not something unfalsifiable. If it is the case (that it is unfalsifiable), then this may hold, but it would also be irrelevant. That is, supply any untestable imaginings and proceed to worry. This cannot be in the direction of any good. Though it is true that scientific achievement is earned through conjecture, it is not true that any idea thereafter is sufficient. There are “good” guesses and “bad”.
So, we can only “reasonably” address this, insofar as we know what it means for there to be a god. More scientifically, we must be able to understand what it would mean if there isn’t. If these conditions are met, then the notion would be either definitively reasonable or not. Given any current (text derived) definition or (the often used) philosophical GOD 4.0, then the conclusion is disagreeable with the proposition.
There are ideas of a god that is non controversial, say Spinoza’s god, but this sort of non-agent is an uncomfortable fit for the god of our concerns. Supplement the label “god” with any ambiguous term in the range of nature and fundamental forces and the redundancy of the label “god” becomes apparent (and unnecessary).
Being agnostic on this subject is take seriously, in some degree, something that cannot provide evidential motivation for concern. It is a truly fascinating delusion.