The Answer to Life, the Universe and Everything Is Forty-Two

Douglas Adams? Deep Thought? Geoffrey Hinton? Apocryphal?

Question for Quote Investigator: The number forty-two is sometimes presented as the answer to life’s deepest question. Where did this answer originate? Who suggested this eccentric and opaque answer?

Reply from Quote Investigator: In 1978 BBC Radio 4 broadcast the science fiction comedy series “The Hitchhiker’s Guide to the Galaxy” created by Douglas Adams. The fourth episode recounted a tale about the answer to humanity’s ultimate existential question.

Millions of years ago a race of hyper-intelligent pan-dimensional beings decided to build a computer called Deep Thought to solve the problem of Life, the Universe and Everything. After the computer was finally built and the question was posed, the response was displeasing. Deep Thought stated that it would require an additional seven and a half million years to arrive at an answer.

After this long waiting period elapsed, a magnificent ceremony took place, and the pan-dimensional beings waited expectantly for an answer. The speakers identified as One, Two, and Three are computer attendants. Boldface added to excerpts by QI:^[1] 1985, The Original Hitchhiker Radio Scripts by Douglas Adams, Section: Fit the Fourth, Quote Page 79, Harmony Books, New York. (Verified with scans)

DEEP THOUGHT: All right. The Answer to Everything …
TWO: Yes … !
DEEP THOUGHT: Life, The Universe and Everything …
ONE: Yes … !
DEEP THOUGHT: Is …
THREE: Yes … !
DEEP THOUGHT: IS …
ONE/TWO: Yes … !!!
DEEP THOUGHT: Forty two.
(Pause. Actually quite a long one)
TWO: We’re going to get lynched, you know that.
DEEP THOUGHT: It was a tough assignment.

Deep Thought indicated that simply knowing the Answer was not enough. The next task was to build an even larger computer with an organic component to determine the Ultimate Question of Life, the Universe and Everything. Deep Thought said it would design the new computer, and it would be called Earth.

Below are three additional selected citations and a conclusion.

A footnote in the book of “The Original Hitchhiker Radio Scripts” included a remark from Douglas Adams about the choice of the number forty-two:^[2] 1985, The Original Hitchhiker Radio Scripts by Douglas Adams, Section: Footnote, Quote Page 88, Harmony Books, New York. (Verified with scans)

Many people have asked whether the choice of forty two as the Ultimate Answer came from Lewis Carroll or perhaps from an ancient Tibetan mystical cult where it is the symbol of truth. ‘In fact it was simply chosen because it was a completely ordinary number, a number not just divisible by two but also by six and seven. In fact it’s the sort of number that you could, without any fear, introduce to your parents.’ (DA)

In 1979 Douglas Adams combined several of his radio scripts to construct the novel “The Hitchhiker’s Guide to the Galaxy”. He rendered the crucial scene as follows:^[3] 1981 (1979 Copyright), The Hitchhiker’s Guide to the Galaxy by Douglas Adams, Chapter 27, Quote Page 179 and 180, Pocket Books, New York. (Verified with scans)

“All right,” said Deep Thought. “The Answer to the Great Question . . .”
“Yes . . . !”
“Of Life, the Universe and Everything . . .” said Deep Thought.
“Yes . . . !”
“Is . . .” said Deep Thought, and paused.
“Yes . . . !”
“Is . . .”
“Yes . . . !!! . . . ?”
“Forty-two,” said Deep Thought, with infinite majesty and calm.

In 2020 Turing-Award winner Geoffrey Hinton who is a leading researcher in machine learning was intrigued by the impressive performance of language model GPT-3 (Generative Pre-trained Transformer 3). Hinton tweeted the following humorous remark:^[4] Tweet, From: Geoffrey Hinton @geoffreyhinton, Time: June 10, 2020, Date: 4:26 PM, Text: Extrapolating the spectacular performance of GPT3 … (Accessed on twitter.com on October 28, 2022) link

Extrapolating the spectacular performance of GPT3 into the future suggests that the answer to life, the universe and everything is just 4.398 trillion parameters.

In conclusion, Douglas Adams deserves credit for writing a scene with a computer named Deep Thought which presented forty-two as the answer to Life, The Universe and Everything. The scene occurred in the 1978 BBC radio program “The Hitchhiker’s Guide to the Galaxy” and its novelization of the same name.

Image Notes: Illustration of a galaxy viewed from a planet surface by Luminas_Art at Pixabay. Image has been resized.

(The tweet from Geoffrey Hinton led QI to explore this topic. The goal was to provide background information to readers to increase the intelligibility of Hinton’s tweet.)