Francis Crick’s Depressing Hypothesis

July 8, 2024 John Horgan

Crick got a kick out of skewering wishful thinking, like my belief in free will. But was he right that we are “nothing but a pack of neurons”? I found this photo of him here.

HOBOKEN, JULY 8, 2024. Only flakes and philosophers fretted over consciousness until the late 1980s. Then Francis Crick, co-discoverer of the double helix, declared that consciousness is a legitimate scientific problem that nitty-gritty brain research can solve. Today, consciousness research is thriving thanks to the efforts of Crick, who died in 2004 at the age of 88. And yet the field is in disarray, with no signs of convergence toward a unifying paradigm. When I watch theorists squabble over whether consciousness pervades all matter or, conversely, doesn’t really exist, I like wondering, What would Crick think? As I hope the profile below (adapted from The End of Science) shows, Crick, whom I interviewed in November 1991 in San Diego, had an uncanny ability to cut through bullshit and get to the bottom of things. That doesn’t mean he was right. -- John Horgan

The ruthless reductionist Francis Crick is not a grim man. Quite the contrary. When I meet him in his huge, airy office at the Salk Institute in 1991, he is wearing a gaudy Hawaiian shirt, and his demeanor is quite jolly. His eyes and mouth curl up at the corners in a wicked grin. His bushy white eyebrows flare out and up like horns. His ruddy face flushes even darker when he laughs, which he does often and with gusto.

Crick seems especially cheery when skewering wishful thinking, such as my hope that we possess free will. Even an act as simple as picking up a pen, Crick reminds me in his crisp Henry Higgins accent, involves vast neural activity.

Crick plucks a pen from his desk and waves it before me. “A lot of computation goes on preparing you for that movement. What you’re aware of is a decision, but you’re not aware of what makes you do the decision. It seems free to you, but it’s the result of things you’re not aware of.”

I frown, and Crick chuckles.

Crick then turns his attention to attention, which together with short-term memory is a key component of consciousness. Making the point that attention involves more than mere perception, Crick hands me a picture and asks what I see. I tell him I see a vase one moment, and the next moment I see two silhouetted, face-to-face profiles.

Crick nods. Although the raw visual input to my brain remains constant, he notes, my attention keeps shifting between two interpretations of that input: vase and profiles. What neural processes underpin this shift? If researchers can find the “neural correlates” of attention, Crick says, they might take a big step toward explaining consciousness.

When you look at consciousness research, do you see a thriving or failing scientific enterprise?

Crick and his collaborator Christof Koch have proposed a tentative answer to the puzzle of attention. Experiments suggest that when the visual cortex is responding to a stimulus, certain groups of neurons fire rapidly, 40 times per second, and in synchrony.

These 40-hertz oscillations, Crick and Koch propose, might correspond to the object of our attention. If one envisions all the neurons in a brain as a vast, chattering crowd, the oscillating neurons are a subset singing the same song. In the case of the vase-profiles pattern, one subset of neurons sings “vase,” another sings “profiles.”

The 40-hertz oscillation theory, Crick acknowledges, has its weaknesses; for example, the best evidence for the oscillations comes from anesthetized--that is, unconscious--cats. The theory is “a good, brave, first attempt,” Crick says, “but I have my doubts that it will turn out to be right.” [See UPDATE below.]

Crick recalls that he and James Watson only decoded the double helix—which turned out to be the key to solving heredity--after numerous false starts. “Exploratory research is really like working in a fog. You don’t know where you’re going. You’re just groping. Then people learn about it afterwards and think how straightforward it was.”

Consciousness and other mind-related puzzles can only be solved with “lots of experiments” on the brain, Crick says. “That’s what science is about.” Cognitive scientists view the brain as a black box, which can be understood in terms of inputs and outputs rather than internal mechanisms.

“Well, you can do that if the black box is simple enough, but if the black box is complicated the chances of you getting the right answer are rather small,” Crick says. “It’s just the same as in genetics. We had to know about genes, and what genes did. But to pin it down, we had to get down to the nitty-gritty and find the molecules and things involved.”

As a Nobel prize winner with an endowed chair, Crick is in an ideal position to promote the investigation of consciousness. “I find the problem fascinating,” he says, “and I feel I’ve earned the right to do what I like.” Crick does not expect researchers to solve consciousness soon. “What I want to stress is that the problem is important and has been too long neglected.”

As Crick speaks, I recall the famous first line of James Watson’s memoir The Double Helix: “I have never seen Francis Crick in a modest mood.” In fact, Crick is often modest, as when he expresses doubts about the 40-hertz oscillation theory. He also says parts of a book he’s writing about consciousness are “dreadful.”

When I mention Watson’s quip, Crick laughs. What Watson meant, Crick suggests, is that he is “full of confidence and enthusiasm and things like that.” Yes, he can be bumptious at times, and critical of others, but that’s because he wants so badly to get to the bottom of things. “I can be patient for about 20 minutes,” he says, “but that’s it.”

Crick’s analysis of himself, like his analysis of most things, strikes me as accurate. He has the perfect personality for a scientist, an empirical scientist, the kind who answers questions, who gets us somewhere. He seems singularly free of self-doubt, wishful thinking and attachment to his own theories.

Crick’s immodesty, such as it is, comes simply from wanting to know how things work. He cannot tolerate obfuscation and untestable speculation. He is also eager to share his knowledge, to make things as clear as possible. This trait is not as common among prominent scientists as you might expect.

In his memoir What Mad Pursuit, Crick reveals that as a boy he dreamed of being a scientist but feared nothing would be left to discover when he grew up. His mother assured him, “Don’t worry, Ducky… there will be plenty left for you to find out.’” Recalling this passage, I ask if Crick thinks there will always be plenty left for scientists to find out.

It depends how you define science, he replies. Physicists might soon determine the fundamental rules of nature, but they can then use that knowledge to invent new things forever. Biology seems to have even more potential. Some biological structures—such as the brain—are so complex that they may resist elucidation for a long time. Historical questions, such as how life began, may never be fully answered because there aren’t sufficient data.

“There are enormous numbers of interesting problems” in biology, Crick says. “There’s enough to keep us busy at least through our grandchildren’s time.” On the other hand, Crick agrees with Richard Dawkins that biologists already have a good general understanding of the processes underlying evolution.

As Crick escorts me out of his office, we pass a table bearing a stack of paper. It is a draft of Crick’s latest book, tentatively titled The Astonishing Hypothesis. Crick asks if I’d like to read his opening paragraph. Sure, I say. The book begins:

“The Astonishing Hypothesis is that ‘You,’ your joys and your sorrows, your memories and your ambitions, your sense of personal identity and free will, are in fact no more than the behavior of a vast assembly of nerve cells and their associated molecules. As Lewis Carroll’s Alice might have phrased it, ‘You’re nothing but a pack of neurons.’”

I look at Crick. He’s grinning ear to ear.

Several weeks later, I call Crick to fact-check an article, and he asks me for advice. His editor isn’t thrilled with the title The Astonishing Hypothesis; she doesn’t think the claim that we are “nothing but a pack of neurons” is all that astonishing. What do I think?

I tell Crick I agree with his editor; his view of the mind is, after all, just old-fashioned reductionism and materialism. I say The Depressing Hypothesis would be more apt but might repel readers. The title doesn’t matter much, I add, since Crick’s fame will sell the book.

Crick absorbs my feedback with his usual good humor. When his book appears in 1994, it is still called The Astonishing Hypothesis. But Crick, or, more likely, his editor, has added a subtitle: The Scientific Search for the Soul.

The subtitle makes me smile. Crick is an adamant atheist. His discovery of the double helix helped crush vitalism, the notion that life is animated by a mysterious and possibly divine essence that resists scientific analysis. Now Crick hopes to stamp out any last vestiges of vitalism through his attack on consciousness. Far from searching for the soul, Crick wants to show that it does not exist. You’re nothing but a pack of neurons.

UPDATE: In 2003 Crick and Christof Koch stated: “We no longer think that synchronized firing, such as the so-called 40 Hz oscillations, is a sufficient condition” for consciousness. Shortly after Crick’s death, Christof Koch embraced integrated information theory, which implies that consciousness is a property not just of brains but of all matter. Today, given all the challenges to his claim that the mind can be explained in neural terms, Crick’s depressing hypothesis should perhaps be called “the dubious hypothesis.” That doesn’t mean he was wrong.

Further Reading:

For a detailed account of consciousness research over the past three decades, see my profile of Christof Koch, “Beyond the Brain,” in my free online book Mind-Body Problems.