Einstein’s 1905 paper came out and suddenly changed people’s thinking about space-time. We’re again in the middle of something like that. When the dust settles, time—whatever it may be—could turn out to be even stranger and more illusory than even Einstein could imagine.

We never really see time. We see only clocks. If you say this object moves, what you really mean is that this object is here when the hand of your clock is here, and so on. We say we measure time with clocks, but we see only the hands of the clocks, not time itself. And the hands of a clock are a physical variable like any other. So in a sense we cheat because what we really observe are physical variables as a function of other physical variables, but we represent that as if everything is evolving in time.

The new coherent picture is not yet available. With all their immense empirical success, G(eneral)R(elativity) and Q(uantum)M(echanics) have left us with an understanding of the physical world which is unclear and badly fragmented. At the foundations of physics there is today confusion and incoherence.

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.

An overly pragmatic attitude is not productive on the long run.

Rationality and the instinct of collaboration have already given us large regions and long periods of peace and prosperity. Ultimately, they will lead us to a planet without countries, without wars, without patriotism, without religions, without poverty, where we will be able to share the world. Actually, maybe I am not sure I truly believe that I believe this, but I do want to believe that I believe this.

I worry that free imagination is overvalued, and I think this carries risks.