Full Idea
A counterfactual can be said to 'backtrack' if it can be said that if the present were different a different past would have led up to it (rather than if the present were different, the same past would have had a different outcome).
Gist of Idea
Counterfactuals 'backtrack' if a different present implies a different past
Source
David Lewis (New work for a theory of universals [1983], 'Dup,Sup,Div')
Book Reference
'Properties', ed/tr. Mellor,D.H. /Oliver,A [OUP 1997], p.208
A Reaction
A nice clear definition of a concept which is important in Lewis's analysis of causation. In the current context he is concerned with elucidation of determinism and materialism. I would say (intuitively) that all counterfactuals backtrack.