This designation, as real, is an important step for modern
science. I don't know how it will turn out, for the better or unfortunate that Feynman chose to continue using the
mathematical term imaginary time. People often think from the tag imaginary that this time is not real. Feynman
recognized that time as we think of it becomes imaginary in this time reference, because this time is totally
indistinguishable from directions in space.
It takes very little reasoning to figure out that if the universe
exists in an unseen way without beginning or end, at right angles to regular time, then that time is simply more
elementary and even more real than ordinary clock time. Thus it seems the term imaginary applies more accurately to our
time. If the universe exists in another time reference where conditions are permanent or static, suddenly it doesn't
matter that we humans so convincingly observe a beginning and a possible future end to our ordinary clock time, since
the other time reference applies regardless of our sense of where we are in time. The universe could be said to exist
before our clock time began, and after time ends. The past and future can be said to exist now. Obviously imaginary time
relates more directly than our own time to existence itself.
Scientifically what you end up with is what Feynman tried to
communicate originally by saying that time is a direction in space. The concept of imaginary time and the no
boundary proposal are still evolving theories, but they do seem to be telling us that the direction of our ordinary
clock time is simply a path toward another place in existence. The past is simply another place in time, as is the
Be aware that such concepts were fostered somewhat quietly by Albert
Einstein, for different reasons, which he derived mainly from relativity. Einstein recognized the possibility that
space-time can be described as a four dimensional existence, rather than as three dimensions that evolve in time. The
only difference in opinion between the two physicists would be that Einstein believed only in our own past and our own
future, concluding that our sense of a present was an illusion. He made statements showing that he believed he himself
existed simultaneously both in his past and future. And if you think about it, this belief is the same as recognizing a
Of course for Einstein the many worlds theory was not even
proposed yet. He didn't seem to ever consider the idea of many possible worlds all existing simultaneously, as we do
today in modern cosmology. On the other hand, Feynman's imaginary time is meant to explain quantum mechanics, which by
many is said to predict all other equally possible worlds, which is known as the Many Worlds
Theory. The term directions in space to Feynman meant all directions, backward and forward in time into other
possible pasts and futures.
In my work I explain what I believe to be the ultimate shape of
the infinite universe, first in the form of an infinite number of spaces. Scientists call this the configuration space
of the universe. I believe the universe is infinite, however, infinite does not simply mean every imaginable world.
Instead I believe every possible space exists as real as the seemingly temporary moments of space we experience, so the
universe is absolutely infinite in that framework. But I was able to create a model describing the overall shape of all
possible universes, all possible other worlds but like our own, ruled by the same laws of nature, all existing
permanently in imaginary time.
I am not sure if Hawking has yet made the final leap to an
infinite space and time cosmological model. He has been conservative at times on the issue of the universe being
infinite either in time or space.
...the universe has not existed for ever. Rather, the universe,
and time itself, had a beginning in the Big Bang, about 15 billion years ago. The beginning of real time, would have
been a singularity, at which the laws of physics would have broken down. Nevertheless, the way the universe began, would
have been determined by the laws of physics, if the universe satisfied the no boundary condition. This says that in the
imaginary time direction, spacetime is finite in extent, but doesn't have any boundary or edge.
I am sure Hawking in the past has been concerned about the
implications of such a theory and the impact it might have upon society, and people's religious beliefs, and himself and
his family. But I have found it interesting that Christian friends have told me the bible actually says this is a period
when we will find out more and more about God. I would think the two time references would correlate well with most
religions, but there is the matter of getting used to it. A lot of people are afraid of change, and I believe that is
healthy to some degree. I can only tell of the personal growth and contentment my own longtime understanding of the
infinite has given me, after having applied such ideology into both my scientific and my own spiritual beliefs.
clearly describes an infinite, or a beginningless and endless time reference with the no boundary proposal.
The no boundary proposal, predicts that the universe would
start at a single point, like the north pole of the Earth. But this point wouldn't be a singularity, like the Big Bang.
Instead, it would be an ordinary point of space and time, like the north pole is an ordinary point on the Earth, or so
I'm told. I have not been there myself.
Using the no boundary proposal, it is fun to imagine the universe
of time from within a globe. Looking up one sees the north pole from the inside. Looking up is looking into the past,
not as if it no longer exists, but instead one can reach up and touch the surface of time as it exists permanently in
imaginary time. The north pole is just a single position upon the rounded surface. So one can reach up and touch the
first moment, or reach down into the past to touch time in the future.
In A Brief History of Time Hawking writes:
One could say: "The boundary condition of the universe is
that it has no boundary." The universe would be completely self-contained and not affected by anything outside
itself. It would neither be created nor destroyed. It would just BE.
Later he writes:
...This might suggest that the so-called imaginary time is
really the real time, and that what we call real time is just a figment of our imaginations. In real time, the universe
has a beginning and an end at singularities that form a boundary to space-time and at which the laws of science break
down. But in imaginary time, there are no singularities or boundaries. So maybe what we call imaginary time is really
more basic, and what we call real is just an idea that we invent to help us describe what we think the universe is like.
I sometimes think Stephen Hawking is being held back, he is way
ahead of everyone else, and so primarily alone and unsupported concerning the issue of an imaginary time reference. In
the latest paper he wrote for a conference on Inflation theory, he advocates a
top-down approach to cosmology. Hawking seems to sense the necessity of a transformation in our view of the physical
universe. This website presents what may be the first complete top-down view
of the universe.
An example of the pressures Hawking deals with is present in an
interview with the BBC radio program Desert Island Discs, this taken from Black Holes and Baby Universes. The
SUE: To oversimplify your theories hugely, and I hope you'll
forgive me for this, Stephen, you once believed, as I understand it, that there was a point of creation, a big bang, but
you no longer believe that to be the case. You believe that there was no beginning and there is no end, that the
universe is self-contained. Does that mean that there was no act of creation and therefore that there's no place for
STEPHEN: Yes, you have oversimplified. I still believe the
universe has a beginning in real time, at the big bang. But there's another kind of time, imaginary time, at right
angles to real time, in which the universe has no beginning or end. This would mean that the way the universe began
would be determined by the laws of physics. One wouldn't have to say that God chose to set the universe going in some
arbitrary way that we couldn't understand. It says nothing about whether or not God exists - just that He isn't
Nice answer Stephen!
The newest development is that Hawking has recently realized that
the no boundary proposal does not require the universe to be closed and finite, as he thought before. In a lecture Inflation;
An Open and Shut Case, Hawking included the following statement.
...I thought the no boundary proposal, implied that the
universe had to be spatially closed, and finite in size. But a few months ago, Neil Turok and I, were talking about his
ideas on open inflation. We realized that they could be fitted in with the no boundary proposal. The universe would
still be closed and finite, in one way of looking at it. But in another, it would appear open and infinite.
One of his many gifts is his ability to translate the math and the
heavy science into more intuitive ideas and symbols which anyone can understand. Clearly, unlike most scientists he
thinks in both ways, and I would relate much of his success to that fact. It has been helpful, even necessary, for me to
utilize Hawking's encompassing mind and his imaginative directions of thought in order to communicate my own theoretical
work which deals with the structure of all possible universes. In one paper I expand upon some of Hawking's descriptive
ideas in order to explain that there isn't simply order and disorder in nature. This would have a great deal of impact
on science and cosmology, and I suppose religion, if in the future we find that it had caught on.