 Another approach proposes that a hypothesis H introduced into a theory T in response to an experimental result E is ad hoc if it is generally unsupported and appears to be a superficial attempt to paper over deep problems with a theory that is actually in need of substantive revision. Thus to level the charge of ad hocness against a hypothesis was actually to direct serious skepticism toward the theory the hypothesis was meant to rescue. This concept of ad hocness arguably makes sense of Einstein’s critique of the Lorentz-Fitzgerald contraction hypothesis as ‘ad hoc’ as a supplementary hypothesis to the aether theory, and Pauli’s postulation of the neutrino as an ad hoc rescue of classical quantum mechanics (Leplin 1975, 1982; for further discussion see Grünbaum 1976).