Full Idea
The 'deductive-nomological' model became known as the 'covering law model': its main thesis is that laws and only laws adequately explain the occurrence of singular events.
Gist of Idea
The 'covering law model' says only laws can explain the occurrence of single events
Source
Stathis Psillos (Causation and Explanation [2002], §8.2)
Book Reference
Psillos,Stathis: 'Causation and Explanation' [Acumen 2002], p.222
A Reaction
But presumably you need other events to derive a law, so you could say that a singular event can only be explained if it isn't singular. A regularity pattern would offer a partial explanation, before any law had been derived.