 SI requires that p be true in the nearby R worlds. When R meets this condition, let us say that R is a safe indicator that p is true. (Different versions of the safety condition have been defended; see, for example, Luper 1984; Sosa 1999, 2003, 2007, 2009; Williamson 2000; and Pritchard 2007.) SI is the contraposition of CR, but the contraposition of a subjunctive conditional is not equivalent to the original.