Michio Kaku

Maxwell's equations... originally consisted of eight equations. These equations are not "beautiful." They do not possess much symmetry. In their original form, they are ugly. ...However, when rewritten using time as the fourth dimension, this rather awkward set of eight equations collapses into a single tensor equation. This is what a physicist calls "beauty," because both criteria are now satisfied.

Remarkably, only a handful of fundamental physical principles are sufficient to summarize most of modern physics.

No other theory known to science [other than superstring theory] uses such powerful mathematics at such a fundamental level. ...because any unified field theory first must absorb the Riemannian geometry of Einstein's theory and the Lie groups coming from quantum field theory... The new mathematics, which is responsible for the merger of these two theories, is topology, and it is responsible for accomplishing the seemingly impossible task of abolishing the infinities of a quantum theory of gravity.

There are many examples of old, incorrect theories that stubbornly persisted, sustained only by the prestige of foolish but well-connected scientists. … Many of these theories have been killed off only when some decisive experiment exposed their incorrectness. .. Thus the yeoman work in any science, and especially physics, is done by the experimentalist, who must keep the theoreticians honest.

It is as inescapable as the laws of physics that humanity will one day confront some type of extinction-level event. But will we, like our ancestors, have the drive and determination to survive and even flourish? . . . On a scale of decades, we face threats that are not natural but are largely self-inflicted [including] global warming . . . modern warfare as nuclear weapons proliferate in some of the most unstable regions of the globe, [or] weaponized microbes [that could conceivably] wipe out 98 percent of the human race. . . . On a scale of thousands of years, we face the onset of another ice age [or] the possibility that the supervolcano under Yellowstone National Park may awaken from its long slumber . . . . On a scale of millions of years, we face the threat of another meteor or cometary impact . . . . We now know that there are several thousand NEOs (near-Earth objects) that cross the orbit of the Earth and pose a danger to life on our planet. . . . If there is one lesson we can learn from our history, it is that humanity, when faced with life-threatening crises, has risen to the challenge and reached for even higher goals. In some sense, the spirit of exploration is in our genes and hardwired into our soul. [So] now we face perhaps the greatest challenge of all: to leave the confines of Earth and soar into outer space. . . . Perhaps our fate is to become a multiplanet species that lives among the stars.

It is sometimes helpful to differentiate between the God of Miracles and the God of Order. When scientists use the word God, they usually mean the God of Order. ...The God of Miracles intervenes in our affairs, performs miracles, destroys wicked cities, smites enemy armies, drowns the Pharaoh's troops, and avenges the pure and noble. ...This is not to say that miracles cannot happen, only that they are outside what is commonly called science.

When Physicists speak of "beauty" in their theories, they really mean that their theory possesses at least two essential features: 1. A unifying symmetry 2. The ability to explain vast amounts of experimental data with the most economical mathematical expressions.

Mathematics... is the set of all possible self-consistent structures, and there are vastly more logical structures than physical principles.

It is often stated that of all the theories proposed in this century, the silliest is quantum theory. In fact, some say that the only thing that quantum theory has going for it is that it is unquestionably correct.

"Killer asteroids are nature's way of asking, 'How's that space program coming along?'" - Anonymous