As Albert Einstein lay on his deathbed, he asked only for his glasses, his writing implements and his latest equations. He knew he was dying, yet he continued his work. In those final hours of his life, while fading in and out of consciousness, he was working on what he hoped would be his greatest work of all. It was a project of monumental complexity. It was a project that he hoped would unlock the mind of God.
“I want to know God’s thoughts”
“I am not interested in this phenomenon or that phenomenon,” Einstein had said earlier in his life. “I want to know God’s thoughts – the rest are mere details.” But as he lay there dying in Princeton Hospital he must have understood that these were secrets that God was clearly keen to hang on to. The greatest scientist of his age died knowing that he had become isolated from the scientific community; revered on the one hand, ridiculed for this quest on the other.
It was a journey that started 50 years earlier in Berne, Switzerland. Then – in his early 20s – he was a young man struggling to make his mark. His applications to universities throughout Europe had all been rejected. In the end his father had pulled strings to get him a job as a third class clerk evaluating the latest electrical gizmos.
But in his spare time he was formulating the most extraordinary scientific ideas. In a single year – 1905, a year that would become known as his miracle year – he published papers that would redefine how we see our world and universe.
Time is relative
He confirmed that all matter was composed of molecules – an idea that at the time was controversial. And most famously of all, he published the paper ‘On the electrodynamics of moving bodies’. It contained his Theory of Special Relativity and suggested that time – something that had always thought to be unchanging and absolute – was relative. It could speed up or slow down depending on the speed you were travelling. From this paper would come an additional three pages, finished in September of the same year, that would contain the derivation of e=mc², the most famous mathematical equation ever written.
Einstein was on a roll. Ten years after his Theory of Special Relativity, he published his Theory of General Relativity – a piece of work widely acknowledged as his masterpiece. The great 17th century scientist Sir Isaac Newton had described the force of gravity very successfully, but what caused gravity remained a mystery. In this Theory of General Relativity, Einstein suggested that gravity was due to the bending of time and space by massive objects. In 1919 astronomers confirmed this by measuring the bending of starlight around the sun during a solar eclipse.
The battle with quantum mechanics
In 1921, Einstein was awarded the Nobel Prize, not for his theories of relativity, but for another paper published in 1905. In this paper, Einstein proposed that light was not simply made up of waves, it could also be thought of as discrete, individual particles or quanta. This discovery would revolutionise physics and chemistry, because it would become one of the foundations of a new science: quantum mechanics.
But during the 1920s the new science of quantum mechanics began to turn the tide against the way Einstein saw the world. Young pretenders in the field of physics had begun to emerge, such as Heisenberg, Bohr and Schrödinger, who are now some of the most famous figures in science. But at the time they were mavericks. They saw quantum mechanics as a brand new way of interpreting everything.
A core element to their new interpretation of the world was that at a fundamental level, everything was unpredictable. You could, for example, accurately tell the speed of a particle but not – at the same time – its position. Or its position but not its speed. It meant that precise predictions were impossible – the best you could hope for was a science based on probabilities.
God does not play dice
Einstein’s work was underpinned by the idea that the laws of physics were an expression of the divine. This belief led him to think that everything could be described by simple, elegant mathematics and moreover, that once you knew these laws you could describe the universe with absolute accuracy. Einstein loathed the implications of quantum mechanics. It was a clash of ideologies.
The conflict reached a crescendo in the late 1920s at the Solvay Conference in Belgium. There Einstein clashed with the great Danish physicist Niels Bohr over the nature of the universe. Einstein constantly challenged Bohr over the implications of quantum mechanics, but never budged from his belief that “God does not play dice”, meaning that nothing would be left to chance in the universe. To which the quantum mechanics community replied: “Einstein, stop telling God what to do with his dice.”
The theory of everything
But Einstein had a trick up his sleeve. He had already begun a piece of work that he believed would ultimately replace quantum mechanics. It would become later known as his theory of everything – it was his attempt to extend general relativity and unite the known forces in the universe.
By completing this theory of everything Einstein hoped he would rid physics of the unpredictability at the heart of quantum mechanics and show that the world was predictable – described by beautiful, elegant mathematics. Just the way he believed God would make the universe. He would show that the way the quantum mechanics community interpreted the world was just plain wrong. It was a project that he would work on for the next 30 years, until the final day of his life.
But while Einstein’s theory of everything may be considered to have been a failure, it is an idea that still fascinates and draws some of the brightest minds in physics. Today many believe that String Theory is our best candidate for a theory of everything. But the ultimate irony is that lurking at the heart of String Theory is the very thing that, because of his beliefs, Einstein had been unable to accept: quantum mechanics.