Don't trust your teachers. - Carlo Rovelli

I argue that the best strategy for understanding quantum gravity is to build a picture of the physical world where the notion of time plays no role at all.

I think that physics is about escaping the prison of the received thoughts and searching for novel ways of thinking the world, about trying to clear a bit the misty lake of insubstantial dreams, which reflect reality like the lake reflects the mountains.

[I]t is the statistical state that determines which variable is physical time, and not any a priori hypothetical "flow" that drives the system to a preferred statistical state. When we say that a certain variable is “the time”, we are not making a statement concerning the fundamental mechanical structure of reality. Rather, we are making a statement about the statistical distribution we use to describe the... properties of the system... The "thermal time hypothesis" is the idea that what we call "time" is the thermal time of the statistical state in which the world happens to be, when described in terms of the macroscopic parameters we have chosen.