I apologize if this seems overly contradictory but I’ll give it a go anyway. I mean no disrespect for the one making this assertion. I just don’t accept it.
“Quite true but I would like to reiterate that you must first know two things - 1. What is the exact amount of fossil fuels on the planet and 2. How are fossil fuels created.”
I am not at all sure that you “must” know these things, for any reasonable definition of the term “know.” In fact, I’m pretty sure you don’t have to know either of these, at all. There is plenty of evidence that is perfectly relevant and should be considered. It’s not perfect, and it’s not complete, and it probably never will be. To treat this otherwise, to demand some form of conclusive proof, or absolute certainty - that would be unreasonable.
Like virtually any system where you don’t see all the inputs, you can nevertheless produce very good estimates, and proceed with a fair degree of confidence in responding to or dealing with the system, based on the outputs of the system.
Do we know with absolute certainty precisely how much oil there is? No. Can we prove that we have all knowledge of all possible methods of petroleum formation? No. And it doesn’t matter all that much either.
We don’t need absolute proof, or complete knowledge, or certainty. We have estimates, concepts, ideas, and approximations based on current experience and current measurement processes. They are sometimes off, sometimes refined - obviously, since it would take a refining of the estimates in order to show that a previous one was off!
Those estimates are perfectly adequate to form conclusions and directions for how to proceed. Absolute certainty is not needed. Reasonable confidence is.
Example from another field: my sons both have special health needs. We have been without health insurance the entire time they’ve been a part of our family (one for 9 years, one for 3 years), which is just to say that health is a big concern, and we spend perhaps more than the usual amount of brain cycles thinking about and being involved in promoting and protecting our family’s health. Our sons (and ourselves, to a lesser degree) are demonstrably sicker when they spend more time at home, and demonstrably happier and healthier when they spend more time away from home. One of our neighbors has lupus, developing symptoms at an unusually early age. Another of our neighbors has breast cancer even though she is from an ethnic group which has a much lower incidence of that disease. Do we have absolute proof of the precise extent of the problem? No. Do we have complete knowledge of how the problem is formed/created? No. Yet in this system where we don’t see all the inputs, we can determine with a fair degree of confidence that we will do well to move to a new home, and we are doing so. To wait for certainty would be foolish. Could we be wrong? Sure, we could. We’re not going to stay here on the off chance that we might be wrong.
Similar example: friends of ours moved into a home. From the time they moved into this home, they got sicker and sicker. They had multiple miscarriages, and a stillbirth. Eventually, neither could work. Some of their relatives moved them to another home to care for them. They recovered within a few days. Can we prove it was the home? No. But it probably was, and it was almost certainly a very very good thing that their relatives didn’t wait till absolute certainty.
Incomplete knowledge is almost always what we have to go on. Indeed, it’s the hallmark of most of human decision making. Only in some branches of mathematics can we reach something like complete knowledge, or certainty. The hallmark of science is that it is constantly challenging its own assumptions, constantly checking and rechecking, refining, and updating. No knowledge there, except in some provisional (soon-to-be-updated) sense.
So I don’t buy the ‘must know’ argument here. Sure, it’d be nice to know those things, and it would make things easier, but not knowing them doesn’t really mean we can’t study and draw very serious conclusions, pro or con, in the peak oil controversy.