A physicist's intriguing metaphysical speculation; God and the New Physics, by Paul Davies. New York: Simon & Schuster. 255 pp. $16 .95.

Paul Davies makes a provocative claim. ''The new physics,'' he writes, ''has overturned so many commonsense notions of space, time and matter that no serious religious thinker can ignore it.''

Einstein's relativity long ago showed time and space not to be absolute concepts but to depend on the state of the observer. Quantum theory has upset classical notions of causality and made the act of observation a crucial part of every physical event. And more recent exploration of the potential for complex organization to transcend what had seemed to be material limitations makes such ''holistic'' phenomena as the human mind or organic life seem much more than interaction of nerves and other material parts.

Certainly there is much in these implications of physics to intrigue religious thinkers. But must they have a university education in physics to appreciate them? This is the real challenge with which Professor Davies confronts his readers.

As a distinguished theoretical physicist at Britain's University of Newcastle-upon-Tyne and a readable popularizer of science, Davies presents the arcane concepts of physics as clearly as lay language allows. But he also knows the limitations of those concepts and the danger of finding a metaphysical meaning in them which simply isn't there. That kind of feel for the subject, which comes only from a deep grasp of physics, is almost impossible to convey. Hence the danger that readers may come away with the impression that the findings of modern physics imply the existence of a spiritual universe beyond material appearance and the omnipresent action of a transcendent God.

This is simply not the case. As Davies himself occasionally points out, physics deals with physical matter. To read more than this into relativity, quantum theory, and cosmology is pure speculation. However, with that caveat firmly in thought, many readers will find Davies's metaphysical speculations insightful and intriguing.

To begin with, he shows clearly that it is just as speculative to conclude, on the basis of physics, that matter is the be-all and end-all of existence as it is to suggest that life, for example, is more than body or mind more than brain. Nothing in any of the sciences has yet elucidated the essential nature of life, thought, or the universe as a whole. What modern physics has done is to cut the ground from the old materialism that tried to explain these things in terms of commonsense simplistic notions of matter and its operations.

The essential questions, Davies says, are: Why are the laws of nature what they are? Why does the universe consist of the things it does? How did those things arise? How did the universe achieve its organization? Davies leaves the reader with these questions. But his essay provides what, for many, will be a new perspective from which to consider them.

In doing this, he observes, ''A growing number of people believe that recent advances in fundamental science are more likely to reveal the deeper meaning of existence than appeal to traditional religion.'' Some traditional religionists may dispute that. But Davies certainly is right when he adds, ''In any case, religion cannot afford to ignore these advances.''

Some physicists also may dismiss this book as unwarranted speculation that goes beyond the bounds of what can be read into physics. So be it. Davies makes no claim to authority. It is a personal essay. And if you take it as such, his book can be a rewarding intellectual romp.