L'univers

whole universe. But humans are a curious species. We wonder, we seek answers. Living in this

vast world that is by turns kind and cruel, and gazing at the immense heavens above, people have

always asked a multitude of questions: How can we understand the world in which we find

ourselves? How does the universe behave? What is the nature of reality? Where did all this come

from? Did the universe need a creator? Most of us do not spend most of our time worrying about

these questions, but almost all of us worry about them some of the time.

Traditionally these are questions for philosophy, but philosophy is dead. Philosophy has not kept

up with modern developments in science, particularly physics. Scientists have become the bearers

of the torch of discovery in our quest for knowledge. The purpose of this book is to give the

answers that are suggested by recent discoveries and theoretical advances. They lead us to a new

picture of the universe and our place in it that is very different from the traditional one, and

different even from the picture we might have painted just a decade or two ago. Still, the first

sketches of the new concept can be traced back almost a century.

According to the traditional conception of the universe, objects move on well-defined paths and

have definite histories. We can specify their precise position at each moment in time. Although

that account is successful enough for everyday purposes, it was found in the 1920s that this

“classical” picture could not account for the seemingly bizarre behavior observed on the atomic

and subatomic scales of existence. Instead it was necessary to adopt a different framework, called

quantum physics. Quantum theories have turned out to be remarkably accurate at predicting events

on those scales, while also reproducing the predictions of the old classical theories when applied to

the macroscopic world of daily life. But quantum and classical physics are based on very different

conceptions of physical reality.

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