The concept of natural vs. non-natural is a human and largely cultural construct.

It’s still a useful word, but it can’t really shoulder the burden of making one argument more rational than the other.

This is off-topic, but I like pointing out that natural does not mean good, especially to hippies at the supermarket who want to pay more for "organic" foods that "aren't full of chemicals". I sympathise with them, but also wish they'd use more appropriate words, and understand the cost of their luxury beliefs.

Tsunamis, earthquakes, flash floods, tornadoes, locust swarms, plagues are "natural". Amanita muscaria, Dendrobatidae and Boa constrictors are "natural" and will fucking kill you.

I think the better distinction is found in Leviathan, contrasting human society (and its set of social contracts) with the "state of nature" - what human life was like before we formed societies:

> In such condition there is no place for industry, because the fruit thereof is uncertain, and consequently no culture of the earth, no navigation nor the use of commodities that may be imported by sea, no commodious building, no instruments of moving and removing such things as require much force, no knowledge of the face of the earth, no account of time, no arts, no letters, no society, and which is worst of all, continual fear and danger of violent death, and the life of man, solitary, poor, nasty, brutish, and short.