Swiss cheese has gaps. The GAP is also a clothing store. Scientific theories do not have gaps. To be sure, practitioners like to talk about their well-knit theories, which invites the attack that the theory in question is riven with holes and gaps. But this is nonsense. And here is how faithful PeP readers can arm themselves against it.
1. State what a "gap" in a theory means: "the gap only reflects, at most, a limitation now existing but in the future to be done away with."
2. Pre-empt the reply that the "gap" proves the theory to be bankrupt: "even if it is true that science has not yet offered an explanation for X, you cannot derive a positive conclusion from this negative fact. Existing ignorance does not justify the assertion of the existence of another region, not very precisely defined, of a different nature wherein supernatural explanations hold sway."