Philosophers such as Dan Brock believe that surrogates who make health care decisions on behalf of previously competent patients, in the absence of an advance directive, should make these decisions based upon a substituted judgment principle. Brock favours substituted judgment over a best interests standard. However, Edward Wierenga claims that the substituted judgment principle ought to be abandoned in favour of a best interests standard, because of an inherent problem with the substituted judgment principle. Wierenga's version of the substituted judgment (...) principle and his counterexample to the principle's successful interpretation of valid surrogate consent is presented. A new version of what is meant by the substituted judgment principle is advanced. The new version is not beset with the problems Wierenga initially ascribed to the substituted judgment principle. (shrink)