This book is an introduction to the esoteric theory of superstrings, a recent theory in physics which purports to unify quantum mechanics and relativity theory. Its principle theme is that such a theory is necessary because by invoking many physical dimensions beyond the familiar 3 (or 4, including time), the laws of physics become simpler, easier to comprehend, and more elegant (beautiful). If Kaku's goal, however, is to demonstrate this to the lay reader, I'm afraid he fails miserably.

A Marxist might initially be attracted to this book after seeing Lenin mentioned positively. Kaku, like many of us, is a product of the 60's, and I believe takes a number of progressive stands on issues like the environment, opposition to nuclear power, and so forth. I seem to remember that he is involved with the Union of Concerned Scientists and may consider himself to be a socialist.

Lenin, in his major philosophical work Materialism and Empirio-Criticism (1908), attacked the idealist physicists and philosophers of his day; individuals such as Ernst Mach and people (including Gorky) influenced by Machian subjective idealism even within the Bolshevik Party itself (the Otzovists, or "God-Builders"). Kaku seems to be agreeing with Lenin when he says that Mach "pointed in the wrong direction, rejecting materialism and declaring that space and time were products of our sensations." [p. 67] Furthermore, Kaku goes on to say:

But despite a few such nice remarks, Kaku is not anything close to a materialist, dialectical or otherwise. In fact the book reeks with all the most absurd idealist craziness that has infected modern theoretical physics to a degree far beyond that which horrified Lenin in his day. To mention a few: parallel universes, time travel, "Creation" (with a capital C, yet!) and the possible existence of God.

Frequently he is a bit wishy-washy in his idealism, but there is still no mistaking it: "the God of Miracles is, in some sense, beyond what we know as science. This is not to say that miracles cannot happen, only that they are outside what is commonly called science." [p. 331] There you have the modern "materialist" physicist; not someone who says (like the notorious Frank J. Tipler) that physics "proves" God exists, and that miracles do occur, but rather someone who just weakly says that God and miracles may exist... Who knows?!

At one place in his book [p. 192] Kaku lists Aquinas's "5 proofs" of the existence of God and notes that science shows that they are fallacious. But he also says that "When scientists use the word God, they usually mean the God of Order" (rather than the God of Miracles). [p. 331] So apparently in his talk of God he is taking the pantheistic view of Spinoza and Einstein that God = Nature. It's a shame Einstein had to sully his otherwise generally materialist outlook with such a view. But with epigones like Kaku, what can you expect!

As I am fond of saying, modern theoretical physics as a whole seems much more like a branch of theology than it does science. Kaku is at best a proponent of "liberation theology" within that idealistic milieu.

Even if you ignore the half (or more) of the book that is tripping off into time-travel, parallel universes, religion, and other LSD-like phantasms, and just look at what Kaku has to say about multi-dimensional unification theories like superstrings, the book is still ridiculous.

One of the major problems with theoretical physics today is just that it is so divorced from the real world, from practice, from experiment. Kaku himself says a couple of times that in the final analysis it is experiment which must show whether superstring theory is correct or not. But there is virtually no reference to experimental data in the book. Instead, we are over and over referred to science fiction themes; we even get an "explanation" of how warp drive works on Star Trek!

Kaku's big excuse is that there is no way to test superstring theory today, and probably won't be for thousands of years! The energy levels necessary, he says, are far beyond anything we can aspire to with present technology. But he also says that the thing the theory really needs is...more theory! He says that if the theory were better developed it should be able to predict the mass of the proton (for example) from prior principles [p. 169]. This would then be some sort of corroboration, at least. [However, it is all too easy to cook up theories that produce "predictions" that you already know the answers to, and then pretend the theory is thus a great success! Cosmologists are always doing this (e.g., with the Big Bang theory); indeed it seems to be their basic modus operandi.]

What we really should say here though is this: If a theory is so undeveloped that it is unable to make testable predictions, then it is at best half-baked. (At worst, it perhaps should not be considered a scientific theory at all yet.)

On the one hand we are told that the theory is mathematically elegant; on the other hand we are told that no one knows how to deal with the mathematics well enough to make a testable prediction. (How elegant is that?!)

On the one hand we are told that this is a break-through theory for understanding all the forces of the physical world; on the other hand it is admitted that "the underlying physical principle behind string theory is unknown". [p. 329]

At this point I start to wonder again just what the virtues of this string theory are supposed to be anyway! Apparently it's undeveloped; mathematically intractable; incomprehensible; outlandish; and untestable! Just what the world of science really needs...

And as presented by Kaku, string theory is essentially idealist besides. Pythagoras and Plato would have loved it; it is one of those theories that claims that matter and energy are composed entirely of "geometry". Although Kaku does not mention it in this book, these "strings of vibrating hyperspace" are assumed in the theory to be strictly one-dimensional, that is to say, geometric objects, not physical objects. He does constantly say in the book that the whole goal is to reduce physics to a geometrical theory. No real materialist can possibly acquiesce in the idea that the world is truly composed of geometric, rather than physical objects. All geometric concepts, such as points, lines and circles, are abstracted from physical objects in the real world, such as tiny things like dust motes, rows of things like pencil lines on paper (which are really composed of numerous graphite particles), etc. But points, lines, and other geometric "objects" do not literally "exist" in the world, and the world is certainly not "made" out of them!

I don't wish to say that a geometrical, multi-dimensional theory like that of Kaluza-Klein or superstrings may not turn out to be of some use in allowing us to fathom and control the world. But if it eventually does so turn out, we will still have to watch out for invalid philosophical nonsense being based on it, the same way we need to do with quantum mechanics at present. (Another major problem with theoretical physics is the constant tendency to be seduced by the mathematics...)

Physics, even more than most other sciences in bourgeois society, is also shown once again to be completely unconcerned with the problems of the people. (Of course, in the hands of the ruling class, it is the creator of many of those problems!) As a bizarre illustration of this, Kaku spends many pages worrying about the "fate of humanity" when the sun explodes in 5 billion years, and when the universe supposedly comes either to a Big Crunch some billions of years after that, or else gradually comes to some kind of "heat death" after 10¹⁰⁰ years or so! He proposes that his superstring theory may save humanity at that time by allowing its escape into "higher dimensions". There is page after page of such bullshit!

As far as I am concerned, if humanity has not replaced itself with something a whole lot better long before the earth disappears then it does not deserve to survive anyway. (If humanity still exists in five billion years it will be because it is a colossal failure, not a great success.) But in any case, it is the more-or-less here-and-now that we need to concern ourselves with, not problems billions or googols of years from now. One might almost have hoped that a "concerned scientist" or "socialist" would take this for granted.

The very first few sentences of the book, in the preface, make two important and valid points:

Those are fine and true words. But do they imply that "anything goes?" or that we can throw out all our common sense, all our good sense, and all our previous science at the drop of a hat? Obviously not; even true words can be taken to ridiculous extremes.

But for Kaku apparently nothing is too ridiculous to take seriously! Nothing! Hopefully some time-traveler will go back and prevent this book from ever being published!

There is a lot more I could say about this book, almost all of it negative. But it comes down to this: I can't recommend it to anybody.