According to theoretical physicist Carlo Rovelli, time is an illusion: our naive perception of its flow doesn't correspond to physical reality. Indeed, as Rovelli argues in The Order of Time, much more is illusory, including Isaac Newton's picture of a universally ticking clock.

What did Einstein say about time being an illusion?

Albert Einstein once wrote: People like us who believe in physics know that the distinction between past, present and future is only a stubbornly persistent illusion. Time, in other words, he said, is an illusion. Many physicists since have shared this view, that true reality is timeless.

Why time is not an illusion?

Time is mysterious; in any relativistic coordinate system, it is linked to space. ... They call the flow of time an illusion. But if the flow of time does not appear in their theory, that doesn't mean that the flow should be dismissed; it means that their theory is incomplete.