Seit Jahrtausenden denken Philosophen über das Wesen der Zeit nach und auch für die moderne Physik ist sie natürlich ein wichtiges Konzept. Deshalb ist es erwähnenswert, wenn mit Lee Smolin einer der klügeren theoretischen Physiker einen Paradigmenwechsel vorschlägt. In seinem neuem Buch Time Reborn: From the Crisis in Physics to the Future of the Universe plädiert er, anders als Einstein, dafür die Zeit als ontologisch realen Gegenstand zu verstehen.

James Gleick schreibt in seiner umfangreichen Rezension Time Regained! in der New York Review of Books darüber:

His argument from science and history is as provocative, original, and unsettling as any I’ve read in years. It turns upside-down the now standard view of Wells, Minkowski, and Einstein. It contravenes our intellectual inheritance from Newton and, for that matter, Plato, and it will ring false to many of Smolin’s contemporaries in theoretical physics.

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For Smolin, the key to salvaging time turns out to be eliminating space. Whereas time is a fundamental property of nature, space, he believes, is an emergent property. It is like temperature: apparent, measurable, but actually a consequence of something deeper and invisible—in the case of temperature, the microscopic motion of ensembles of molecules. Temperature is an average of their energy. It is always an approximation, and therefore, in a way, an illusion. So it is with space for Smolin: “Space, at the quantum-mechanical level, is not fundamental at all but emergent from a deeper order”—an order, as we will see, of connections, relationships. He also believes that quantum mechanics itself, with all its puzzles and paradoxes (“cats that are both alive and dead, an infinitude of simultaneously existing universes”), will turn out to be an approximation of a deeper theory.

For space, the deeper reality is a network of relationships. Things are related to other things; they are connected, and it is the relationships that define space rather than the other way around. This is a venerable notion: Smolin traces the idea of a relational world back to Newton’s great rival, Gottfried Wilhelm Leibniz: “Space is nothing else, but That Order or Relation; and is nothing at all without Bodies, but the Possibility of placing them.” Nothing useful came of that, while Newton’s contrary view—that space exists independently of the objects it contains—made a revolution in the ability of science to predict and control the world. But the relational theory has some enduring appeal; some scientists and philosophers such as Smolin have been trying to revive it.