Peak Oil is an observation, not a "theory".

Actually, it's a natural phenomena, not an observation :)

Oh, I just have to disagree. "Natural" means something of nature, does it not? As opposed to something done by man, which is regarded as "artificial". Now I know some argue that man is part of nature, therefore everything we do is "natural", but that is a semantic argument which is meaningless, as most semantic arguments are (ref: philosophy).
So my point is that resource depletion is caused by man, and is therefore artificial, not natural. "Nature" isn't depleting the oil, man is.
PO is still an observation.

No it is a natural phenomenon. Any species that comes across a huge amount of detritus, left by past life, will naturally consume it until it is all gone.

Ron Patterson