The Now

The Now is the term Einstein gave to the present moment. But as he lamented, there is no such thing in the physics. As Carnap describes:

Once Einstein said that the problem of the Now worried him seriously. He explained that the experience of the Now means something special for man, something essentially different from the past and the future, but that this important difference does not and cannot occur within physics. That this experience cannot be grasped by science seemed to him a matter of painful but inevitable resignation.

Physicist David Mermin explains the issue very clearly in his article in Nature:

My Now — my current state of affairs — is a special event for me while it is happening. I can tell my Now from earlier events, which I only remember, and from later events which I can only anticipate or imagine. The status of an event as my Now is transitory: it becomes a memory as subsequent Nows emerge.
Yet clear, evident and banal as this is to us all, there is no Now in the usual physical description of space and time. Physicists represent all the events experienced by a single person as a line in four-dimensional space-time, called that person’s ‘world-line’. There is nothing about any point on my world-line that singles it out as my Now. (2014)

The picture below symbolises a sequence of moments in my life. So this represents a little segment of my worldline.

A segment of a worldline illustrated as a sequence of views of reality
A sequence of moments in life.

Each two-dimensional picture symbolises the three-dimensional physical reality, in a specific state, at a specific moment in time. So each one is a static moment along my worldline. Each one is what Weyl calls ‘a section of this world’ in his longer statement:

The objective world simply is, it does not happen. Only to the gaze of my consciousness, crawling upward along the life line of my body, does a section of this world come to life as a fleeting image in space which continuously changes in time. (1949, 116)

This is what happens as the experiencing consciousness sweeps through these moments, up the worldline of the body. There is the experience of reality, moment after moment, each one a fleeting image of spatial reality. Thus the static world comes to life as the sequence of moments is experienced. That is what Weyl is saying.

As a result, there is the effect of time passing as moment after moment is experienced in sequence. This is how consciousness gives rise to the experience of the passage of time, as he describes.

This is not a new idea. As stated by Arthur Eddington, physicist and philosopher of science:

Events do not happen: they are just there, and we come across them [as] the observer on his voyage of exploration. (1920)

When you take a train journey, it is clear that you are passing through the landscape of the track. Obviously, the landscape is not moving. It is just your view of the landscape that is changing. But inside the train, from your moving viewpoint, you experience the passage of the landscape. Weyl is saying that the experience of the passage of time is exactly the same kind of thing. The world simply is. It does not change at all. What is changing is the perspective of the moving viewpoint. As the moving viewpoint of consciousness, the Now, passes along the track of the worldline, into the future in the space-time layout, there is the effect of the passage of time.

The Future

The strange thing that is so hard to grasp is that all the future moments exist already. It seems I must have already done all the things I am going to do. Of course, it would be rather disconcerting to realise it is all predetermined. But it is only predetermined in terms of probabilities. This is the nature of the quantum universe.

One specific path into the future is only one of the infinity of possible paths. And as described in The New Empowerment, we are constantly shifting and changing the definition of of the future, and thus the path of the worldline in the personal world. So the movie of life is already written, but there is an infinity of choice points. And which version you will witness is the great mystery, and the extraordinary opportunity.

The Now is the moving viewpoint of consciousness. This gives rise to the movie of life. As Tegmark says, quoted in The Block Universe, life is like a movie, and space-time is like the DVD. And consciousness is like the DVD player.