The vertiginous symptoms of skepticism can be hard to distinguish from the pangs of love. At first it was just a teenage infatuation. I was 16. He was … older. I wrote his name on my lined recycled A4 notepad, where it nestled among doodles of spiraling tendrils and ballerinas. He made me uneasy in a good way. And he made me laugh; he had this way of expressing himself that made it difficult to tell if he was being sincere or tongue in cheek.

Nearly thirty years later, he still gives me butterflies. Of course, we’ve had our ups and downs. But, somehow, we’ve made it through. So this Valentine’s Day, I wanted to pay tribute to what is, by far, my most enduring romantic relationship.
Without further ado:
Roses are red,
violets are blue.
David Hume,
I made this playlist for you.
1. Katy Perry, “Chained to the Rhythm.”
This one speaks to you both lyrically and sonically. Perry sings about a dystopian world in which we’re all “chained to the rhythm”—that is, to our comfortable routines.
Yeah, we think we’re free
Drink, this one’s on me
We’re all chained to the rhythm
To the rhythm, to the rhythm
Sound familiar, Dave? Cast your mind back to Book 1 of your Treatise (1739-40, Part 3, Section 11): “The supposition, that the future resembles the past, is not founded on arguments of any kind, but is derived entirely from habit, by which we are determined to expect for the future the same train of objects, to which we have been accustomed.” And, of course, as you go on to show in Book 2 of the Treatise (Part 2, Section 4), this point extends to those that we keep near and dear to us: “When we have contracted a habitude and intimacy with any person; though in frequenting his company we have not been able to discover any very valuable quality, of which he is possessed; yet we cannot forebear preferring him to strangers, of whose superior merit we are fully convinced.” In other words, you were saying that we love the ones we’re with because they’re … well, they’re there and it would so bloody exhausting and inconvenient to find other people. You old romantic, Dave!
Meanwhile, the song’s catchy dancehall, disco elements ensures that it elicits the same beguiling effects against which it warns. Its rhythm chains us to the rhythm. I think you’d cop to using that trick, too, Dave—that is, exploiting your reader’s susceptibility to the very forces to which you’ve just noted she, and all humans, are especially vulnerable. “Carelessness and in-attention,” you remark, “alone can afford us any remedy” from skepticism’s vertiginous truths. “For this reason,” you admit you’re not too worried about your readers falling prey to the skeptical malady, relying entirely on their short attention span which ensures that “whatever may be the reader’s opinion at this present moment, that an hour hence he will be persuaded there is both an external and internal world” (Treatise, Book 1, Part 4, Section 2). In other words, just like Perry, you realize that we’re all chained too tightly to the ordinary world’s rhythms to break free from them, just as I’m all too tightly chained to you, Dave.
2. The Shirelles, “Will You Love Me Tomorrow.”
If it’s custom and habit that makes you stick to what you know and love those you love, then your critique of induction, Dave, can’t help but make a girl wonder “why we should extend that experience beyond those particular instances, which have fallen under our observation” (Treatise, Book 1, Section 6)? Or, in the words of The Shirelles, “Tonight the light of love is in your eyes / But will you love me tomorrow?” Given your conviction, Dave, that “fidelity is no natural virtue,” and that “Nothing is more fluctuating and inconstant on many occasions, than the will of man,” I think you’d find yourself in agreement with the skeptical sentiments so eloquently expressed in “Will You Love Me Tomorrow” (Treatise, Book 3, Part 2, Section 5, and Book 2, Part 1, Section 10). As you put it yourself, “Now it is evident, that wherever a person is in such a situation with regard to me, that there is no very powerful motive to deter him from injuring me, and consequently it is uncertain whether he will injure me or not, I must be uneasy in such a situation, and cannot consider the possibility or probability of that injury without a sensible concern” (Book 2, Part 1, Section 10). Put more starkly, Dave, if the sun coming up tomorrow is already subject to doubt, The Shirelles’s suspicion that their hearts will “be broken /When the night meets the morning sun” (or doesn’t, as the case may be) seems all the more warranted.
3.
Dave, I struggled over this one, which I wanted to find a song that could embody that one particular shade of blue. You know the one:
Let all the different shades of that colour, except that single one, be placed before him, descending gradually from the deepest to the lightest; it is plain, that he will perceive a blank, where that shade is wanting, said will be sensible, that there is a greater distance in that place betwixt the contiguous colours, than in any other. Now I ask, whether it is possible for him, from his own imagination, to supply this deficiency, and raise up to himself the idea of that particular shade, though it had never been conveyed to him by his senses? I believe there are few but will be of opinion that he can. (Treatise, Book 1, Part 1, Section 1)
I started out with Taylor Swift’s “Blank Space.” Too Lockean. Not blue enough. Then I tried Miles Davis’s “So What” from Kind of Blue. Too abstract. Then Joni Mitchell’s “Blue.” It worked lyrically (“Underneath the skin / An empty space to fill in”) but it was too stripped down. Siouxie and the Banshees, “Something Blue”? Too lavish. Too much blue. Finally I thought I had it: “A Missing Shade of Blue,” by Dida Pelled. Dave, it came so close. And by just missing the mark it gave me an idea. You see, if you line up all of these blueish songs together (a playlist within a playlist, if you will), descending gradually from the deepest to the lightest, then it is plain, you will perceive an interval, where that pitch of blue is missing. Now I ask, Dave, whether it is possible for you, from your own imagination, to supply this deficiency, and raise up to yourself the idea of that particular pitch, though it had never been conveyed to you by your senses? I believe there are few but will be of opinion that you can. Are you trying, Dave? Can you hear the mermaids singing? I do not think they will sing to me. But never mind, heard melodies are sweet, but those unheard are more azure, etc.
4. Janet Jackson, “If.”
First off, Dave, you’d love this video, which highlights the discontinuous, mediated nature of perception and, also, the sickest, most sinuous choreography you’ve ever seen. Ms. Jackson at her finest. Second off, you know how you’re credited for originating all the philosophical conversations we have today about counterfactual theories of causation, but how what you said was so tantalizingly brief? Viz., “if the first object had not been, the second never had existed.” (1748, Enquiry Concerning Human Understanding, Section VII). Just imagine how you might have dilated upon these lyrics if Jackson’s song had been around in the eighteenth century!
If I was your woman
The things I’d do to you
But I’m not
So I can’t
Then I won’t
But
If I was your girl.
But it wasn’t
So you couldn’t
And you didn’t. Oh well.

5. Fine Young Cannibals, “I’m Not the Man I Used to Be.”
This one’s pretty straightforward. “But it’s plain to see / I’m not the man I used to be,” croons Roland Gift, lead singer and finest of the Young Cannibals, who has clearly cottoned onto the fact that he is “nothing but a bundle or collection of different perceptions, which succeed each other with an inconceivable rapidity, and are in a perpetual flux and movement,” and so “The identity, which we ascribe to the mind of man, is only a fictitious one” (Treatise, Book 1, Part 4, Section 6). “Wonder what I’m thinking / Wonder why I’m drinking”? Well, it’s obvious why: the intense view of these manifold contradictions and imperfections in human reason has so wrought upon him, and heated his brain, that he is ready to reject all belief and reasoning. And that’s why he’s drinking, because reason is incapable of dispelling these clouds. He should hang in there and have a bite to eat and ideally play a game of backgammon, right Dave?
6. Stevie Wonder, “Superstition.”
This one’s almost too obvious except … here’s the twist: a tension between content and form distinguishes both this classic and your own treatment of superstition, Dave. Because both music and philosophizing as you well know act upon us in ways that we don’t fully understand. It’s all very well for you and Stevie Wonder to disavow superstition: “When you believe in things that you don’t understand / Then you suffer Superstition ain’t the way.” Fair enough. “Nor does the wolf molest more the timid flock, than superstition does the anxious breast of wretched mortals” (Dialogues on Natural Religion, 1779). Sure. But … I don’t understand Mr. Wonder’s musical genius (that’s him on the harmonica too on track #8!) and I believe in it. Likewise, skepticism may just be a philosophical thought experiment, but it nonetheless has the power to plunge one into the deepest of psychic darknesses, Dave (see your Treatise, Book 1, Part 4, Section 7).
7. Natalie Imbruglia, “Torn.”
Let’s dwell in the darkness a little while, Dave. “Torn” might seem like a counter-intuitive track to add to this list but, trust me: you and Natalie Imbruglia are kindred spirits. (And, yes, Dave, we both know she didn’t write it, but I think we’d also both concur that her version left the deepest impression.) “Torn” is essentially the Conclusion to Book 1 of the Treatise in musical form. It reads less as an anatomy of a couple’s break up and more as an anatomy of the philosophical self’s break up. That might just be me. But it’s indisputable that “Torn” brings together many of your favorite themes, Dave. To wit:
Ms. Imbruglia: “There’s nothin’ where we used to lie / Conversation has run dry.”
Dave: “what cou’d be expected from Men who never consulted Experience in any of their Reasonings, or who never search’d for that Experience, where alone it is to be found, in common Life and Conversation?” (“Of Essay Writing,” 1742).
Ms. Imbruglia: “Illusion never changed / Into something real.”
Dave: “If our senses, therefore, suggest any idea of distinct existences, they must convey the impressions as those very existences, by a kind of fallacy and illusion” (TreatiseBook 1, Part 4, Section 2).
Ms. Imbruglia: “I’m all out of faith / This is how I feel.”
Dave: “I begun this subject with premising, that we ought to have an implicit faith in our senses … But to be ingenuous, I feel myself at present of a quite contrary sentiment, and am more inclined to repose no faith at all in my senses” (Treatise, Book I, Part 4, Section 2).
Ms. Imbruglia: “So I guess the fortune teller’s right / I should have seen just what was there / And not some holy light.”
Dave: “Experience only teaches us, how one event constantly follows another; without instructing us in the secret connexion, which binds them together” (Enquiry Concerning Human Understanding, Section 7, Part 1).
Ms. Imbruglia: “I’m already torn.”
Dave: “Let it be taken for granted, that our perceptions are broken” (Treatise, Book I, Part 4, Section 2).
In other words, Dave, you and Natalie concur: we’re all already torn.
8. Chaka Khan, “I Feel for You.”
Enough with the moping cold and naked on the floor … Let’s warm ourselves up again, Dave. “Baby, baby, when I look at you I get a warm feeling inside.” Or, in your own, only slightly less catchy words, Dave, “My heart catches the same passion, and is warmed by those warm sentiments, that display themselves before me” (Treatise, Book 3, Part 2, Section 3). Sing it! None of your cerebral Adam Smithian sympathy here! No, “It’s mainly a physical thing /This feeling that I got for you, baby,” because Prince (who wrote the song) and Chaka Khan understand that feelings are embodied. They agree with you that “[t]he passions are so contagious, that they pass with the greatest facility from one person to another, and produce correspondent movements in all human breasts” (Treatise, Book 3, Part 2, Section 3). Chaka Khan’s words echo those rapped by Melle Mel, affirming that the passage of the passions is, in fact, bi-directional. Moreover, the song’s exuberant instrumentation—drum-machines; synthesizers; harmonica—attests that, as you say, “[t]he passions may express themselves in a hundred ways,” without words (Treatise, Book 2, Part 2, Section 6).
9. Ella Fitzgerald, “Isn’t it a Pity.”
The last two songs, Dave, shift the focus out from you to, well, us.
Imagine all the lonely years we’ve wasted,
Fishing for salmon,
Losing at backgammon!
What joys untasted,
My nights were sour,
Spent with Schopenhauer!
Your fondness for backgammon is well established. I’m not sure whether you were a keen angler, Dave, though surely, as a Scot, you appreciated salmon. But then, I’ve never read Schopenhauer either, so let’s not get bogged down by the details. “Isn’t it a Pity” was originally a duet written by the Gershwins for the ill-fated Broadway show Pardon My English (1933). As a duet, the wistful refrain, “Isn’t it a pity we never met before!” expresses the couple’s mutual wish that they had met before a today in which they have found one another. The song becomes stranger and better suited to us, Dave, as a solo performance, because one can’t help wondering whether the speaker’s first-person plural—“Here we are at last, / It’s like a dream, / The two of us, a perfect team”—reflects reality or fantasy. Sung as a solo, the speaker’s ardent enthusiasm seems slightly stalkerish (“Meeting you today / Has given me a wonderful idea – / Here I stay!”). The final line’s reaffirmation that “it’s such a pity we never, never met before!” only reinforces the impression that the speaker’s view of her beloved is most powerfully colored by her sense of what can never never be.
10. Crowded House, “You’re Not the Girl You Think You Are.”
The theme of fantasy carries over into my final song, Dave, a waltz in a minor key full of word play and images of optical distortion, in which phantoms of personhood beguile and misdirect. The Finn brothers sing:
You’re not the girl you think you are, yeah
There’s someone standing in your place
The bathroom mirror makes you look tall,
But it’s all in your head, in your head
Like “Isn’t it a Pity,” on first listen, “You’re Not the Girl You Think You Are” resembles a romantic ballad. But, the more you listen to it, the more it feels less about a romance and more about the fictions with which we soothe ourselves. In a poignant symptom of something like a collective determination to make the song fit a romantic template, almost all available transcriptions of the lyrics mis-transcribe one key word.
He won’t deceive you
He’ll tell you the truth
Woman, he’ll be no trouble
He won’t write you letters
Full of excuses
C’mon, believe you have one in a million
But the lines are not “He won’t deceive you / He’ll tell you the truth”; they are “He won’t deceive / Or tell you the truth.” That little “Or” is crucial because it captures the key virtue of the imaginary lover: his lack of existence makes him blessedly incapable of either inveigling one with lies or haranguing one with grim truths. His absence (“those aren’t his shoes under your bed”) is precisely what makes him “no trouble,” is what ensures “he won’t write you letters / Full of excuses.” In short, the imaginary lover’s absence is what makes him—what makes you, dearest Dave—one in a million.
Sarah Tindal Kareem is Associate Professor of English at the University of California, Los Angeles, where she teaches and researches eighteenth-century literature including but not exclusively limited to the works of David Hume. She is currently working on a book about literary attachment. With Crystal B. Lake, she is co-founder and editor of The Rambling. She also regularly writes Notes from the Duck-Rabbit Hole. You can find her on Twitter @stkareem.