Brief Answers to the Big Questions

by Stephen Hawking

This was the development of language, and particularly written language. It meant that information could be passed on from generation to generation, other than genetically through DNA. There has been some detectable change in human DNA, brought about by biological evolution, in the 10,000 years of recorded history, but the amount of knowledge handed on from generation to generation has grown enormously. I have written books to tell you something of what I have learned about the universe in my long career as a scientist, and in doing so I am transferring knowledge from my brain to the page so you can read it. The DNA in a human egg or sperm contains about three billion base pairs of nitrogenous bases. However, much of the information coded in this sequence seems to be redundant or is inactive. So the total amount of useful information in our genes is probably something like a hundred million bits. One bit of information is the answer to a yes/no question. By contrast, a paperback novel might contain two million bits of information. Therefore, a human is equivalent to about fifty Harry Potter books, and a major national library can contain about five million books—or about ten trillion bits. The amount of information handed down in books or via the internet is 100,000 times as much as there is in DNA. Even more important is the fact that the information in books can be changed, and updated, much more rapidly. It has taken us several million years to evolve from less advanced...