This quote is actually from a talk given by Swami Vivekananda in the US in 1895, in which he is recorded as having said:
The whole secret of existence is to have no fear. Never fear what will become of you. Depend on no one. Only the moment you reject all help are you free.
The fact that the talk was delivered over a century ago made me wonder when people started talking about a “secret of existence.” It struck me as being rather a 19th century expression.
Google Books only gives one result from the 18th century for that phrase, one more (excluding duplicate results) from 1800 to 1820, and then dozens from 1820 to 1830. Even allowing for sample bias in Google’s database, it seems that the phrase only came into vogue in the early 1800s — earlier than I’d thought.
The phrase “the secret of life” seems to have become common much earlier, and is found in books throughout the 1700s.
Even earlier was the phrase “secret of Nature,” which I’ve seen in many books as far back as the 1500s.
When the Buddha talked about “secrets” or things being “secret” he seems to have done so in quite a literal way. He’d talk about people doing evil deeds in secret, and about friends keeping your secrets and sharing their own. But he doesn’t seem to have talked about a “secret of life” or a “secret of existence.”
Nowadays “secrets of life” abound. It seems that many people have discovered this secret and will sell you it in paperback, hardcover, or in ebook format.
Thanks for Bhikkhu Pandit for sending me this quote, which he found on Facebook.
This Fake Buddha Quote also crops up from time to time on Twitter: