When I bought my bike, I've been told that I should make sure the tires are well inflated because this reduces the risks of having a flat tire when rolling over sharp objects, and that it was easy to understand why.
However, after almost a year later, I still haven't figured out why it would be the case, although I guess this is correct.
Here are my thoughts:
A well inflated inner tube can be considered as a torus with a greater volume than deflated inner tube. It also should have a reduced thickness, making it easier to pinch, I believe. An analogy would be an inflated balloon. If it's near exploding, its thickness surface is lesser than a deflated balloon, and I suppose it's also easier to pinch. I wonder why it wouldn't be the case for inner tubes of tires.
According to several sources on the Internet (as well as one here), when one gets a flat tire, riding a bike becomes much harder due to increased rolling resistance. The usual reason given is that it takes a lot of energy to deform the tire, which is what happens while rolling with a flat tire. So a lot of energy spent with the legs is being used to deform the tire (and inner tube) rather than making the bike go forward. If that's true, then a sharp object should have a harder task to pinch a deflated tire than to pinch a well inflated tire. That's because a deflated tire would have to deform a lot before getting drilled by the sharp object, while the fully inflated tire wouldn't be able to deform much before getting drilled. So one would spend less energy to pinch a well inflated tire than to pinch a more deflated tire.
Thus, I am unable to find a good reason of how a well inflated tire would resist more to sharp pinching objects than a deflated tire. I'd appreciate if someone could point what I'm missing and how it counters the two points I made above.
As a sidenote, the optimal pressure of the inner tube of my bicycle is 2.5 bar to 4 bar. One can assume that by well inflated tire I meant 4 bar and by deflated tire I meant 2.5 bar. By flat tire I meant 1 bar (atmospheric pressure).