The argument from nature, the argument from self-interest, and the argument against practical effects. The first argument against euthanasia is the argument that it is natural for all of us to prolong our lives, to protect ourselves from death, like all other animals in the animal kingdom. It is enough, I believe, to recognize that the organization of the human body and our patterns of behavioral responses make the continuation of life a natural goal. By reason alone, then, we can recognise that euthanasia sets us against our own nature. Humans have a natural goal to continue their life.
Natural goals are morally right.
Euthanasia goes against the natural goal of continuing life. Therefore, euthanasia violates the natural goal and is morally unacceptable. This argument by Ray V. McIntyre is cited by J. Gay-Williams, and McIntyre states that it is our natural goal to prolong life, therefore we should always prolong life. This argument is not convincing because as soon as he says that natural goals should be followed, it could be argued that we should not use contraception for example, because it is our natural goal to reproduce. Also the natural goal of avoiding pain conflicts with the natural goal of prolonging life.