BOOK REVIEW : Struggle to Discover Method of the Mind : SPECULATIONS, The Reality Club <i> edited by John Brockman</i> ; Prentice Hall Press, $10.95 paperback, 256 pages

Science, after all, is limited. In the areas where it holds sway--physical reality--it has no equal in its ability to understand the world and its power to affect it. But it cannot know everything. Values and morals, for example, elude scientific proof.

Where are the limits? How much can science know? Questions along this frontier turn out to be devilishly difficult and so far unresolvable. Is there a complete physical explanation for the experience we call mind? Is there a mechanical equivalent of consciousness? If you think so, you say we haven’t got it yet. If you think not, you say it can never be found. No one knows who’s right.

Questions of this kind lurk at the heart of many areas of study, and they are always fascinating even if they cannot be answered. Some have been around since the Greeks invented knowledge and Plato was dean of the Academy. They include fundamental truths about truth itself. Science rests on them, but they are apparently beyond scientific proof themselves.

Since 1981, a rotating group of--for lack of a better word--intellectuals has met monthly or so in New York to discuss these matters and see what headway they might make on them. This group, the Reality Club, has heard papers principally from scientists and philosophers, 13 of which are collected in this volume, “Speculations,” edited by John Brockman, the club’s founder.

These essays, provocative, lively and informative, focus on aspects of the human mind, which remains the most complicated and elusive object of scientific study. The brain, whose extraordinary powers make science possible, resists the scientific method.

There are many theories and there is a large amount of data, but no one knows how the brain works. How you are reading these words and making sense of them is, as the Germans say, unangreifbar beim heutigen Stand der Wissenschaft --unassailable at the current state of knowledge.

So it is appropriate for philosophers to get in on the act, and here we find, for example, Daniel C. Dennett, the distinguished arts and sciences professor at Tufts University, asking, “How is human consciousness situated in the world? That is a great, ancient problem of philosophy, but also one of the most perplexing unanswered questions of science.”

Dennett discusses Von Neumann machines, which would work like computers, and goes on to hypothesize about the workings of what he calls a Joycean machine, “since it is the stream of consciousness we are modeling.” He concludes:

“Where does the mind come from? Is it real? What is it made of? It is a virtual machine, running in the brain, a product of three sorts of evolution. And it is its own user illusion.”

Nicholas Humphrey, a British theoretical psychologist, wonders what evolutionary advantage consciousness afforded those who had it. What advantage does consciousness give to creatures who are able to think about themselves (us) so that they have survived and others have not?

“We have an idea of what consciousness is doing--namely, giving the subject a picture of his own brain activity--but we have no idea yet about what biological good that does him in the context of his daily life,” Humphrey writes.

Morris Berman, a social critic and essayist, wonders about a related topic: what happens when there’s too much consciousness or a heightened consciousness, which may be related to artistic sensibility or to creativity itself. He is drawn to the subject of the tortured artist, and he thinks about the “peculiar tendency” of creativity “to burn out or destroy the artist, often at a relatively young age.”

He distinguishes various kinds of creativity and attempts to put it all together in a theory, but, as is common in this sort of enterprise, the questions are more impressive than the answers.

Why do we think about these things at all? Why are we curious? Where does our urge to know come from? Who is this person I call I? Where are my thoughts and emotions? Do they have physical reality? These questions underlie all others, and for reasons unknown, thinking about them is very pleasurable even if we are a long way from knowing the answers.

“Speculations” offers a first-rate collection of current thinking on the subject.

Next: Jonathan Kirsch reviews “Maps to Anywhere” by Bernard Cooper (University of Georgia Press).