An appeal to nature is an argument or rhetorical tactic in which it is proposed that "a thing is good because it is 'natural', or bad because it is 'unnatural. It is generally considered to be a bad argument because the implicit (unstated) primary premise "What is natural is good" is typically irrelevant, having no cogent meaning in practice, or is an opinion instead of a fact. For example, it might be argued that polio is good because it is natural. In practice, polio has little to recommend it, and if there were any good effects to be found, they would not be specifically because it's a natural disease, as an artificial disease could well have the same properties. Forms General form of this type of argument: In some contexts, the use of the terms of "nature" and "natural" can be vague, leading to unintended associations with other concepts. The word "natural" can also be a loaded term – much like the word "normal", in some contexts, it can carry an implicit value judgement. An appeal to nature would thus beg the question, because the conclusion is entailed by the premise. Opinions differ regarding appeal to nature in rational argument. By some more permissive views, it can sometimes be taken as a helpful rule of thumb in certain limited domains, even if it admits some exceptions. When such a principle is applied as a rule of thumb, natural facts are presumed to provide reliable value judgments regarding what is good, barring evidence to the contrary, and likewise for unnatural facts providing reliable value judgments regarding what is bad. Within a limited domain, treating a rule of thumb such as "all else being equal, you should generally try to eat natural foods" as if it is an exceptionless principle can sometimes involve a fallacy of accident. Julian Baggini explains the standard view of what makes this a fallacy as follows: "Even if we can agree that some things are natural and some are not, what follows from this? The answer is: nothing. There is no factual reason to suppose that what is natural is good (or at least better) and what is unnatural is bad (or at least worse)." History The meaning and importance of various understandings and concepts of "nature" has been a persistent topic of discussion historically in both science and philosophy. In Ancient Greece, "the laws of nature