by Jason Stotts
Teleology is the field of philosophy concerned with achieving ends (telos is Greek for “end”). In teleology, one judges the efficacy of the means in question to achieve a particular end. For example, if my goal is to write a sentence on a piece of paper, then a pen is “good” for this end, while a leaf is not. In teleology, one is merely judging the efficacy of a particular means of achieving a particular end. Importantly, one is not judging the end. Rather, the only thing in question in teleology is the efficacy of the means to achieve the end. Those means that can fulfill the end in question are teleologically good, while those means that cannot fulfill the end in question are teleologically bad. Further, some means are teleologically better for achieving ends and vice-versa.
Ethics, on the other hand is the field of philosophy that is concerned with human action. Consequently, Ethics is concerned both with the ends that people choose and with the means they employ to achieve those ends. In order for Ethics to operate, an ultimate end must be identified by which all other ends and means will be evaluated; that is, Ethics relies on an ultimate end as a standard. For example, in Utilitarianism the ultimate end is the greatest good for the greatest number, in christianity the ultimate end is their god’s will, in Aristotelianism the ultimate end is Eudaimonia, in Objectivism the ultimate end is an individual’s life, etc. Once an ultimate end is chosen for the ethical system, then the system operates teleologically with one judging the efficacy of means and lesser ends (which are also means to larger ends). Thus, ethics is a sub-set of teleology. This is important to understand as the converse is not true: teleology is not a sub-set of ethics just as it is that case that all dogs are mammals, but not all mammals are dogs.
It is also important to understand that the ultimate goal of ethics is not a part of ethical system in the same way as other parts of the system. The ultimate goal of an ethical system is the standard by which the rest of the system is judged and cannot itself be subject to judgment within the ethical system of which it is the ultimate goal as it cannot be the standard by which it is itself judged. Thus, a Utilitarian cannot morally judged the principle of Utility as it forms the basis for his ethical system. This does not mean that ultimate ends cannot be judged, but rather only that they cannot be judged within the framework of their own systems. However, they can be judged epistemologically, metaphysically, logically, etc. Further, ultimate ends can be attacked based on the reasons for which they were postulated as ultimate ends. For example, since there are no reasons to believe in a god, any system of ethics that relies on a god can be attacked epistemologically for failing to have reasons for belief. It is, however, dubious to attack one ethical system with another directly (even if one can prove that one’s ultimate end is true both metaphysically and epistemologically).