We are in pre-collapse. It it is hard to argue collapse has not begun.
Okay, I'll bite. For real collapse to have begun, we would need a windup to a 15-20% decrease in human population. How about 5%? When the population drops 5% across a year, I'll give you that we've got one decent windup coming for collapse. But let's say, as some might, that a real collapse as I've outlined is too severe. People dying off in large numbers, hard to grasp based on the world we were all raised in, so let me ask, prior to claiming anything is pre-collapse, what is your definition of collapse? We need that to be able to figure out any precursors to it. My definition is easy to calculate a pre-collapse, human population decreases year over year, or three. Like the Black Plague in the chart I provided prior. That could be considered a pre-collapse, a warmup to the main event. But in that case, and by definition using mine, a pre-collapse is possible THAT DOESN'T TURN INTO A REAL COLLAPSE. I'll stipulate to that one.
So, what is your definition of collapse, that we might speculate on what a "pre" might look like?
If everyone got smart, an impossibility. collapse could be avoided for centuries. But the truth is we are past a dozen tipping points. It is only a matter of time now.
That is a claim that has been around 1970 Earth Day when the collapse was supposed to arrive via overpopulation and pollution. What is a tipping point called when it DOESN'T tip? And can it be used again without an explanation for why it didn't work the last time someone tried it out?
Civilization will return when intelligent squirrels find RE's tombstone and extract the info about the original Diner from the digital archive in the stone.
How does civilization relate to your definition of collapse? As RE pointed out, the Roman Empire collapsed, but human population did not. So an empire, or even civilzation collapsing, is not itself a collapse severe enough to trigger the metrics I've laid out for my definition.
Consider this: 
The picture is 'in denial' of collapse in a way. It suggests 'we' can adapt. One side of the road still lives. If we can always adapt there will be no collapse. A ridiculous perspective. Thinking there is always a way ignores how much human flesh is alive. Math says we will collapse.
Okay, I agree that math says we will collapse. Physics even more so. It is a given, because the Sun is getting lighter, and as it gets lighter it burns hotter, and our planet has the oceans boiled away, and long before that, we will have collapsed. Excluding the astrophysical (a nice GRB would be terribly entertaining for a short period of time as well) I also agree that adaption itself does not stop collapse.
Without oil there are far to many to feed. Social breakdown is inevitable, but we are not there yet.
Well, good thing we don't appear to be without oil yet then? Even better, places like America have more of it, and fewer to feed, than places like India.