It's the question we all face occasionally - and usually set aside for later. What is the meaning of life? Fortunately, one of the world's top thinkers, renowned for his discoveries in superstring theoryAn attempt to explain all of the forces of nature by modelling them as vibrations of tiny supersymmetric strings., has an answer. 

Physicist Brian Greene's book Until the End of Time is 400-pages long, subtitled "mind, matter and the search for meaning in an evolving universe" and tackles "the most fundamental questions of existence"¹. Here, to make things easier, is his thesisA long essay involving personal research. in six paragraphs:

The Universe will end. The two great principles of the Universe are evolution (things are constantly coming together in new combinations) and entropyA gradual decline into disorder., which means that everything falls apart after time. They are constantly fighting it out, but entropy will win in the end. The Universe will become ever bigger and colder, the sun will go out and even atomsThe smallest unit of any chemical element. will dissolve.

Everything is connected. It is wrong to see ourselves as separate from the rest of the universe. We are literally made of stardustMatter from stars that exploded. and everything about us, including our ability to think, has evolved according to the same laws as everything else. Recognising that we are part of a much greater reality lets us see our lives in an exciting new way.

Humans are significant. In cosmicRelating to the universe or cosmos. terms, human existence is the blink of an eye. Yet in science and the arts, we have achieved extraordinary things that may not be matched in a billion years. Striving for such achievements, together with our love for others, is what gives purpose and meaning to our lives.

Science should respect religion. Science does not have all the answers. It is useful in exploring external reality, but there are other ways of trying to understand life. Religion helps us explore our own consciousness and our place in the universe as a whole.

Schools test too much. Science is not about passing exams. There is no single way to solve a problem: what matters is looking for answers in inventive ways. Education should aim to free young minds to think creatively and originally.

Time travel is possible. If you travelled in a rocket at the speed of light for six months, then returned to Earth, thousands of years would have passed. We just need to develop the right rocket.

So, what does this mean? Some say that because we are such tiny specks in a vast universe, it is ridiculous to think that our lives have any purpose or significance. It is a flukeAn unlikely chance occurrence. that our planet happens to support life, and equally lucky that we have evolved into what we have. If we did not exist, it would make no difference to anything in the great scheme of things. Our eventual extinction will go unnoticed.

Others argue it is because we are tiny specks that we can be said to have a purpose. Logically, a race of our size should be of no significance. But it is perverseBeing deliberately unreasonable, awkward or illogical. to pretend that art like the Mona LisaAlso known as the Giaconda, a portrait by the Italian artist Leonardo da Vinci. It became one of the world's most famous paintings after a successful robbery in 1911. , or a discovery like superstring theory, is of no importance. If we have the ability to achieve such things, pursuing them must be our reason for being here.

Yes: An individual human life may be short, but in its thousands of years of existence the human race has achieved incredible and extraordinary things. Our lives have clear meaning.

No: Every civilisation eventually comes to an end. One day, all traces of human life will have disappeared, alongside our knowledge and accomplishments. It is naive to pretend otherwise.

Or... Meaning does not have to be on a grand scale. We may not be certain of our future in the universe, but every person can find meaning in their own life through their actions and relationships.