ok i was thinking you were comparing the two acts, rather than just devaluing the underlying argument of 'natural must mean good'. I'd forgotten about the lions (where a new male will enter the pride and kill all the cubs so the females would go into estrus sooner and could bear his seed). It just goes against my grain to talk about infanticide as natural... since when I talk about an act as natural, I tend to take the reference as 'something that cannot be helped because it's natural behavior.' Darwinism aside, I can't think of a legitimate reason for infanticide. Point taken though.
I think the 'natural' argument of marijuana is related to the 'not as harmful as other drugs' one. Marijuana contains everything you need to get high, and only requires some drying before it can be consumed. When I pit this against how synthetic drugs are produced (and the effects they have on the body), I would say that marijuana is a better, more 'natural' option. I see what you mean though. I wouldn't say hemlock is a great drug, simply because it is natural
