**Table of Contents**

*.......The Elegant Universe*

**THE ELEGANT UNIVERSE,****Brian Greene,**1999, 2003

```(annotated and with added

**bold highlights by Epsilon=One**)

**Chapter 12 - Beyond Strings: In Search of M-Theory**

Does Any of This Solve the Unanswered Questions in String Theory?

Yes and no. We have managed to deepen our understanding by breaking free of certain conclusions that, in retrospect, were a consequence of perturbative approximate analyses rather than true string physics. But the current scope of our nonperturbative tools is quite limited. The discovery of the remarkable web of duality relations affords us far greater insight into string theory, but many issues remain unresolved. At present, for example, we do not know how to go beyond the approximate equations for the value of the string coupling constant—equations that, as we have seen, are too coarse to give us any useful information. Nor do we have any greater insight into why there are precisely three extended spatial dimensions, or how to choose the detailed form for the curled-up dimensions. These questions require more sharply honed nonperturbative methods than we currently possess.

What we do have is a far deeper understanding of the logical structure and theoretical reach of string theory Prior to the realizations summarized in Figure 12.11, the strong coupling behavior of each string theory was a black box, a complete mystery. As on maps of old, the realm of strong coupling was uncharted territory, potentially filled with dragons and sea monsters. But now we see that although the journey to strong coupling may take us through unfamiliar regions of M-theory it ultimately lands us back in the comfortable surrounds of weak coupling albeit in the dual language of what was once thought to be a different string theory.

Duality and M-theory unite the five string theories and they suggest an important conclusion.

The challenge to the string theorist—or perhaps we should say the M-theorist—is to show that

What we do have is a far deeper understanding of the logical structure and theoretical reach of string theory Prior to the realizations summarized in Figure 12.11, the strong coupling behavior of each string theory was a black box, a complete mystery. As on maps of old, the realm of strong coupling was uncharted territory, potentially filled with dragons and sea monsters. But now we see that although the journey to strong coupling may take us through unfamiliar regions of M-theory it ultimately lands us back in the comfortable surrounds of weak coupling albeit in the dual language of what was once thought to be a different string theory.

Duality and M-theory unite the five string theories and they suggest an important conclusion.

**It may well be that there aren't other surprises, on par with the ones just discussed, that are awaiting our discovery.****(Epsilon=One: You over rate your accomplishments, which barely scratch the surface of knowledge and wisdom; and, your "surprises" do little to explain known enigmas or to internally reconcile the Standard Model physics theories. i.e. What is a "field"?; What is mass?; What accounts for "positive" and "negative" charges?; Where has "anti"-matter gone?; Why the Inverse Square Law (ISL)?; Why does "spin" behave the way it does?; Why do numbers (and mathematics) explain Nature so well?; Why the Heisenberg Uncertainty Principle (HUP)?; et cetera . . . almost ad infinitum.)**Once a cartographer can fill in every region on a spherical globe of the earth, the map is done and geographical knowledge is complete. That's not to say explorations in Antarctica or on an isolated island in Micronesia are without scientific or cultural merit. It only means that the age of geographic discovery is over. The absence of blank spots on the globe ensures this. The "theory map" of Figure 12.11 plays a similar role for string theorists. It covers the entire range of theories that can be reached by setting sail from any one of the five string constructions. Although**we are far from a full understanding of**the terra incognita of**M-theory**, there are no blank regions on the map. Like the cartographer, the string theorist can now claim with guarded optimism that the spectrum of logically sound theories incorporating the essential discoveries of the past century—special and general relativity; quantum mechanics; gauge theories of the strong, weak, and electromagnetic forces; supersymmetry; extra dimensions of Kaluza and Klein—is fully mapped out by Figure 12.11.**(Epsilon=One: Extra dimensions beyond the four obvious, "standard" dimensions borders on the ludicrous until such dimensions are defined. Possibly, theorists are defining forms of oscillation as dimensions. The Pulsoid is an amalgam of nine different oscillations which establish all phenomena of***Reality*and are the ultimate "building blocks" of all that exists.)The challenge to the string theorist—or perhaps we should say the M-theorist—is to show that

*some*point on the theory map of Figure 12.11 actually describes our universe. To do this requires finding the full and exact equations whose solution will pick out this elusive point on the map, and then understanding the corresponding physics with sufficient precision to allow comparisons with experiment. As Witten has said,**"Understanding what M-theory really is—the physics it embodies—would transform our understanding of nature at least as radically as occurred in any of the major scientific upheavals of the past."***15*This is the program for unification in the twenty-first century.**(Epsilon=One: No! M-Theory has no first postulate. And, theoretical physicists seem to lack the ability to go beyond the quantitative, which is a requirement if the locus of the Universe is to be understood.)**