In discussing his definition, Wreen noted the difficulty of justifying euthanasia when faced with the notion of the subject's "right to life". In response, Wreen argued that euthanasia has to be voluntary, and that "involuntary euthanasia is, as such, a great wrong". Other commentators incorporate consent more directly into their definitions. For example, in a discussion of euthanasia presented in 2003 by the European Association of Palliative Care (EPAC) Ethics Task Force, the authors offered: "Medicalized killing of a person without the person's consent, whether nonvoluntary (where the person is unable to consent) or involuntary (against the person's will) is not euthanasia: it is murder. Hence, euthanasia can be voluntary only." Although the EPAC Ethics Task Force argued that both non-voluntary and involuntary euthanasia could not be included in the definition of euthanasia, there is discussion in the literature about excluding one but not the other.