As a follow up to my recent discussion of final and efficient causes, I’d like to draw your attention to what is surely the creepiest song of the seventies: Tony Orlando singing “Knock three times.” The song tells the story of some lonely guy in a darkened apartment fantasizing about the girl upstairs. Apparently because he can hear her listening to music he envisions her dancing. While she doesn’t know who he is he knows her well. (Can you say “stalker”?) As the song progresses he develops in his delusional state a schizophrenic morse code by which he believes she can communicate with him through the floor. (Remember, she doesn’t even know this psycho exists. She’s probably washing dishes and innocently listening to the radio while in his delusional state he envisions her “swaying to that smoky beat”, to borrow a line from Bob Segar.)
And so he unfolds his delusion:
“Knock three times on the ceiling if you want me.”
“Twice on the pipe” *knock knock* “if the answer is no.”
“Oh my sweetness” *thump thump thump* “means you’ll meet me in the hallway.”
“Twice on the pipe” *knock knock* “means you ain’t gonna show.”
Here’s how it looks for a non-delusional person. Mr. Lonely Hearts is sitting in his dark apartment — no doubt with the curtains drawn — and intently listening for sounds in the apartment building. Any sounds he hears will immediately be interpreted not as random knocks or thumps created by efficient causes alone, but as intentional modes of communication from the woman upstairs (final causes) inviting him up for, ahem, a spot of tea.
Remember, she doesn’t even know he exists by his own admission.
What happens when this fruit loop heads upstairs and she doesn’t show? Shiver. (This is but one step away from Motley Crue singing “You’re all I need.”)
So there you have it: the creepiest song of the 70s. And now you have one very disturbing illustration of why it is essential to distinguish knocks and thumps that are mere events due to efficient causes from those which are the results of final causes due to an intelligent agent.

