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.

Listening a cultivated person of today that jokes and almost boasts about his scientific ignorance, is as sad as listening a scientist that boasts about not having read any poem.

I think that the resistance against Darwin is not just the difficulty of seeing the power of a spectacularly beautiful explanation: it is the fear of realizing the extraordinary power that such an explanation has in shattering rests of old world views.

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

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

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.

The very foundation of science is to keep the door open to doubt. Precisely because we keep questioning everything, especially our own premises, we are always ready to improve our knowledge. Therefore a good scientist is never ‘certain’. Lack of certainty is precisely what makes conclusions more reliable than the conclusions of those who are certain: because the good scientist will be ready to shift to a different point of view if better elements of evidence, or novel arguments emerge. Therefore certainty is not only something of no use, but is in fact damaging, if we value reliability.