Actually we aren't. The definition we as a species have given to the word "natural" means outside of human activity and influence.

Other than that I agree with everything else, however.

The category we as animals have given to the word "ordinary" means outside of human activity and influence.

"natural" comes from the Latin 'nascor'='I am born'. That which is natural is that which is born, or so one could argue.

I had best defer to the venerable Yale historian John Boswell who, in his work 'Christianity, Social Tolerance, and Homosexuality', insisted that:

"Although concepts of "ideal nature" resemble and are strongly influenced by meanings of "real nature," they differ significantly from the latter in explicitly presupposing that "nature" is "good." Whether "ideal nature" is understood to include all physical things or simply the nonhuman, it is always believed to operate to the "good." Some "natural" things may be sad or distressing, may even give the appearance of evil, but all can be shown to result in something which is desirable or worthwhile in the long run or on a grand scale. Anything which is truly vicious or evil must be "unnatural," since "nature" could not produce evil on its own. Concepts of "ideal nature" are strongly conditioned by observation of the real world, but they are ultimately determined by cultural values [emphasis added]. This is particularly notable in the case of "unnatural," which becomes in such a system a vehement circumlocution for "bad" or "unacceptable." Behavior which is ideologically so alien or personally so disgusting to those affected by "ideal nature" that is appears to have no redeeming qualities whatever will be labeled "unnatural," regardless of whether it occurs in ("real") nature never or often, or among humans or lower animals, because it will be assumed that a "good" nature could not under any circumstances have produced it."

Boswell, John Christianity, Social Tolerance, and Homosexuality, Chicago University Press, 1981, page 13.

He goes on to argue that:

"The idea that homosexuality is "unnatural" (perhaps introduced by a chance remark of Plato) became widespread in the ancient world due to the triumph of "ideal" concepts of nature over "realistic" ones. Especially... following the rise of Christianity, philosophical schools of thought using idealized "nature" as the touchstone of human ethics exercised a profound impact on Western thought and popularized the notion that all nonprocreative sexuality was "unnatural.""

Boswell, John Christianity, Social Tolerance, and Homosexuality, Chicago University Press, 1981, pp 13-14.

Several pages are devoted to the argument, but that is the gist of it.

To say that nonprocreative sex is unnatural is to insist that that which is natural requires a birth to result, from a different reading of the etymology given at the beginning; however, I remind you that that would exclude a great deal of the so-called "natural world," which includes elements seen as "natural" but is not responsible for birth. Opium, for instance, is considered a 'natural' drug, while hydromorphone is a 'synthetic' drug. One comes from a plant, while the other goes through a belabored process to end with a more potent, quality-controlled and regulated product. A desert landscape is viewed as a scenery of 'nature', though it is quite possible that nothing visible is not sand, which is not alive and definitely does not procreate: "Nature" has been adapted by mankind to mean something which exists outside of the sphere or human activity, provided that it is morally defensible.

One can say that nature is that which we say it is; however, humans have a long history of being fickle and discriminatory. Morals, words, philosophies change with the times.

"Nature" is distinct from the "supernatural" and the "unnatural" and the "nonnatural". The usage of these words is purely emotional, and as such lacks the rigorousness required for validation. "Supernatural" refers to something seemingly above "nature", but typically desirable and cherished (depending, of course, on the supernatural actor). "nonnatural" is an essentially neutral term by which one can refer to that which is man-made but not morally distasteful: fibers, the hydromorphone example above, etc. Finally, "unnatural" denotes implicitly that something is shunned by convention. Ironically, a great deal of the "unnatural" aspects of the world and that within the world is actually "natural" in the most meaningful sense of the term, but is called such merely to give credence to the notion that it is wrong.