Source for the "monsters under our bed" quote attributed to Darwin

Question

I'm trying to locate the source of the famous quote usually attributed to Darwin (and sometimes, The Joker...):

We stopped looking for monsters under our bed when we realized that they were inside us.

Google books and Archive.org only gave me secondary quotes, without any sources. In the following book on Darwin, I thought a source was mentioned (The Expression of the Emotions in Man and Animals) but it seems that it only concerns the following quote, as I searched the whole book, without finding it: Darwin on Evolution on Google Books.

I'm starting to think it has been mistakenly attributed to him, but it might be from letters or others documents not available online, so I would like to be proven wrong.

Answer 1

The earliest version of this quote that I was able to find appeared on Twitter in 2009.

RT @iamsuperhero: we stopped looking for monsters under our beds because we realised they were inside us.

_{@tinkeringbeII, 2009-10-19 10:32. twitter.com.}

Note that this is a retweet (from the days when retweets had to be done by hand), so the quote is older than this, but the retweeted account is locked, so I was unable to trace it further back. The quote became popular on Twitter: if you do your own searches, you'll find many hundreds of instances in many modified versions (“stop” for “stopped”; “the monsters”; “underneath” for “under”; “when” for “because”; and so on).

So I think that pending an earlier discovery, a likely origin is on Twitter, perhaps from user @iamsuperhero, or perhaps from another user whose account has been locked or deleted.

From Twitter the quote made its way to other social media sites and eventually into print. The earliest printed instance I can find is in Passionaries (2013), a young-adult paranormal romance by Tonya Hurley:

‘They say that we stop looking for monsters under the bed when we realize they’re inside of us,’ he paused. ‘Just as we stop looking for evil. There’s evil inside all of us, Cecelia. You are no different.’

_{Tonya Hurley (2013). Passionaries, p. 119. London: Hodder.}

The quote was soon mis-attributed to Darwin. The earliest instance I can find is Charles Darwin: His Words (2014) by Daniel Coenn, a self-published e-book. A printed book with the mis-attribution appeared in 2015 (this is the one referred to in the question):

We stopped looking for monsters under our bed when we realized that they were inside us.

It is always advisable to perceive clearly our ignorance.

— from The Expression of Emotion in Man and Animals

_{Anon, ed. (2015). Darwin on Evolution: Words of Wisdom from the Father of Evolution, p. 46. New York: Skyhorse.}

These collections of quotations are very quick and cheap to publish, and often contain revealing errors suggesting that they were copied from other collections of quotations, and not from original texts. They should never be depended on for scholarship or evidence. In the Skyhorse case, the quotation “it is always advisable to perceive clearly our ignorance” is genuine, but the book was titled The Expression of the Emotions in Man and Animals (not “Emotion”), suggesting that the editor at Skyhorse had consulted a secondary source like Coenn, and not the original work. Presumably the “monsters under the bed” quotation got in via a similar reliance on secondary sources.

Answer 2

It might be a lot newer than that. From Angela Panayotopoulos's The Wake Up (2018), in an excerpt found on the publisher's website (emphasis mine):

I remember begging my father to check under the bed. I remember trying to explain how some monsters had invisibility cloaks. He would kiss my cheek and switch off the light.

We stop looking under the bed once we realize that the monsters are inside us.

It’s funny how they transform. Suddenly they don’t mind daylight. Suddenly they dress nicely, speak our language, and share our customs. They sit next to us on the metro and jog around our neighborhoods. They slip things into our drinks at parties and offer us jobs. Sometimes we spot them, sometimes we don’t.

Of course, this book might have simply grabbed the idea/quote from an older work. But Google Ngrams shows no results (in the maximum available year range of 1500 to 2019) for "monster[s] under our bed[s] when", in any of its four possible variants.

I've also tried searching the web for assorted variants of this phrase while excluding "Darwin" and "Joker" from search results, but then the only thing remaining is websites that don't cite any source at all, plus this Goodreads page citing The Wake Up.