So I've read Henri Bergson's Laughter, a book on comedy and humourous things.
I've also read Sigmund Freud's The Uncanny (Das Unheimliche) on what we find scary.
And I see so many similarities between the scary and funny that I think they're closely related.
Yet neither Freud nor Bergson (contemporaries) makes this comparison, only focussing on their specific topic, either laughter or fear.
Is laughter fear in reverse and vice versa, and has anyone written about this specifically?
Both Freud and Bergson present examples that are strikingly similar but from different perspectives.
I will try to do it short:
Animation of dead objects, like talking dolls can be scary, but is also a much used humourous effect, like when animals talk in cartoons or fairy tales.
But to freud reanimation is a manifestation of childhood memories when we didn't distinguish between the dead and living.
(Children actually see their toys as living beings, but as adults we forget/suppress this, and find it scary to be confronted with it again - like a tree at night that looks like a person, or living dead etc.).
Repetition is something Bergson sees as fundamentally humourous. The clown constantly dropping his hat to pick up something he lost, only to lose it again when he graps the hat, in a loop...
Humans behaving mechanical is also, to Bergson, comical, and part of the repetition theme (he goes on at length about this).
But to Freud repetition, such as compulsions to do the same things over and over, is 'uncanny' and frightening. He also mentions doppelgängers and déjà vu.
Warped objects, things taking unusual forms or sizes can be funny, like when Alice in Wonderland grows tiny and enormous, or just a regular object in grotesque size.
But Freud mentions how this is also inherently scary, as it literally warps our perception of reality.
Surprises are a key element in much humour, like the end of a joke taking a turn we didn't expect, or the magician pulling out a rabbit from his hat.
Or just think of a surprise party where the surprised person is thrilled and then laughs. (The word thrilled is ambiguous and means both fear and joy).
But in other scenarios we all know how surprises are scary, even if there's nothing to fear.
(If a person expects something scary they will react with fear. Just think of children not being scared of dangerous animals they've never encountered before).
Some would argue it's not the same. It's simply the context that determines what is funny or scary.
But the fundamental traits of humour and fear appear to have similarities.
https://en.wikipedia.org/wiki/Uncanny
https://en.wikipedia.org/wiki/Laughter_(book)