So yesterday there I was—sitting in a fancy conference room with a new client (an emeritus professor) and three of the team members of his project, which includes the book I’m editing. They’re asking questions. My opinions. I’m trying to remember a really famous book, mainstream metaphysics, to use as an example. The title won’t come. The name of the famous author won’t even come. So I think (and talk) fast and use a different book to make my point. The meeting goes on. When it ends, the professor hands me a check and escorts me through the lobby to the gate. Cordial conversation. When do I remember the book title and author? About four hours later.

Mind fade? I don’t think so. Here’s a piece I wrote about five years ago on why we forget. I just remembered where I’d filed it.

We hear it all the time. Someone forgets what he was supposed to buy at the grocery store and picks up a dozen cans of Spaghetti-O’s and when he gets home and his wife asks why, he says, “Oh. I must’ve had one of them senior moments.” Or someone else confuses the names of her dozen grandchildren or forgets people’s names at a party. “Gee,” she says with a nervous laugh, “I guess it must be early-onset Alzheimer’s.”

Don’t you believe it. Alzheimer’s is a dreadful, wretched disease that eats our brain and spits it out in pieces. I remember when it hit my grandfather. My grandparents had been married more than fifty years, and Grampa forgot who his wife was. He called her “old woman.”

During the 1990s, I spent several months as a paid companion to a woman named Fran. I’d known Fran “before.” She’d been a successful businesswoman. When I started spending time with her, she was eighty-two years old…and mentally about two. I took her for walks. I also read to her before I helped her undress and put her to bed. We both got bored really fast with the books (Erma Bombeck and romance novels) from the assisted living complex’s library. I brought books from home. You know what she enjoyed listening to? Jeeves and Wooster. A book of goddess stories. But she spent most of her time in another world, arguing fast and furious with invisible people from her childhood. At the time I was writing Secret Lives, so I spent a lot of time listening to and watching invisible people. Fran and I made a good pair. She’d have an occasional moment of clarity (I could see it in her eyes), and I’d say, “Fran, this is hard, isn’t it?” and she’d say, “Yes”—and go right back into her awful world.

Alzheimer’s is one of the top ten causes of death today. It’s the only disease we cannot prevent, slow down, or cure. A few months ago, one of the columnists set out to distinguish between normal ageing and Alzheimer’s. Missing an occasional monthly credit card payment is something we all do, whereas becoming totally unable to manage a budget is a sign of Alzheimer’s. Forgetting what day it is once in a while is normal; losing a whole week or month or season is Alzheimer’s. Occasionally misplacing your car keys is normal, but misplacing your whole house is Alzheimer’s. Not liking to cook anymore is normal; turning on a burner and leaving it on all night is Alzheimer’s. Forgetting the occasional name or word (“but it’s on the tip of my tongue”) is normal; being unable to conduct a conversation is Alzheimer’s.

We all forget stuff. I edit books written by people as young as thirty. My oldest author was a man aged ninety-two. Across the entire age range, my authors make incorrect word choices and forget details like their characters’ names. That’s normal. Fortunately, I can supply the correct word (or at least make a good guess) and scroll back to find a character’s name when he or she first entered the plot. I can usually unscramble plot complications that don’t make sense.

But there are mornings when I wake up with a snatch of music or lyrics (for example) in my head, and it takes all day for me to remember where it came from. And I’ve never been good at remembering names. I have therefore created a theory to explain this kind of memory loss. See if it works to you.

You know those huge paper files that some offices still have? Go to almost any doctor’s office, for example, and you’ll see those long rows paper files. The lives of hundreds of people. Now visualize a room filled with five-drawer filing cabinets. Visualize every drawer in every one of those filing cabinets stuffed with paper files—notes, agendas, memoranda, reports, summaries of everything we ever saw on TV or in a movie, term papers and theses, business and friendly letters, every song we ever heard, text messages and voicemail…you name it, it’s there in drawers so full you can’t close them anymore. That’s your head. As we age and see more and read more and hear more, the little daimon (the Greek word for the invisible presence that accompanies us through our lives, a sort of talkative guardian angel) in our head is taking notes on everything and putting the notes in our mental files. Everything we do. Everything that happens to us every second of every day. Everyone we meet. Everyone we talk or text to and what we tell them. The longer we live, the more files pile up in our head. At some point, all those papers burst out of their file drawers. At some point, we get papers all over the floor of our head. It’s in stacks and the stacks fall over. As long as we’re alive, that enormous collection of imaginary paper records of our lives is flying, zooming, buzzing around in our heads.

So ask yourself…what were you supposed to stop and buy for supper tonight? What are the names of all your neighbors/cousins/grandchildren? Where’s that Visa bill you thought you paid already? When is your anniversary? When is your best friend’s birthday? Where’s the receipt the plumber gave you to give the landlord? Where is…? Where did you put…? When did…? Who was…? (And it’s even more fun if you read as much history as I do.)

Get the idea? Take another look at that file room in your head. Even if it’s a hard drive (or a cloud) instead of paper files, maybe your personal search engine’s sick in bed with a cold. The word I want might be “on the tip of my tongue,” but actually it’s somewhere in the piles of paper on the floor of my brain. Yeah. That’s why I can’t immediately identify a phrase from an Ira Gershwin lyric and why you keep using the wrong words in your book or the memos you write. Give us enough time, and, yeah, we can sift through all those mental files until we find what we almost have in hand.