V. S. RAMACHANDRAN is the director of the Center for Brain and Cognition at the University of California, San Diego, and an adjunct professor at the Salk Institute, La Jolla. He is the author of Phantoms in the Brain: Probing the Mysteries of the Human Mind.
I am a brain, my dear Watson, and the rest of me is a mere appendage.
—SHERLOCK HOLMES
An idea that would be “dangerous if true” is what Francis Crick referred to as “the astonishing hypothesis”—the notion that our conscious experience and sense of self consists entirely of the activity of 100 billion bits of jelly, the neurons that constitute the brain. We take this for granted in these enlightened times—but even so, it never ceases to amaze me. Some scholars have criticized Crick’s tongue-in-cheek phrase (the title of his last book) on the ground that the hypothesis he refers to is neither astonishing nor a hypothesis, since we already know it to be true. Yet the far-reaching philosophical, moral, and ethical dilemmas it poses have not been recognized widely enough. It is in many ways the ultimate dangerous idea.
Let’s put this in historical perspective.
As Freud once pointed out, the history of ideas in the last few centuries has been punctuated by revolutions—major upheavals of thought that have forever altered our view of ourselves and our place in the cosmos. First, the Copernican system dethroned the earth as the center of the cosmos. Second, the Darwinian revolution introduced the idea that, far from being the climax of “intelligent design,” we are merely neotonous apes that happen to be slightly cleverer than our cousins. Third, the Freudian view taught that even though you claim to be in charge of your life, your behavior is in fact governed by a cauldron of drives and motives of which you are largely unconscious. And fourth, the discovery of DNA and the genetic code implies, to quote James Watson, that “[t]here are only molecules. Everything else is sociology.”
To this list, we can now add a fifth: the neuroscience revolution and its corollary, pointed out by Crick—the astonishing hypothesis that even our loftiest thoughts and aspirations are mere byproducts of neural activity. We are nothing but a pack of neurons.
If all this seems dehumanizing, you haven’t seen anything yet.
This dangerous idea will lead to a philosophical dilemma that will emerge three hundred to five hundred years from now, when we completely understand the brain. But let’s speculate: Imagine that today a neuroscientist can transplant your brain into a vat filled with a culture medium and artificially create patterns of activity that will make you feel as though you are living the lives of, say, Francis Crick, Bill Gates, Hugh Hefner, and Mark Spitz, with a dash of Mohandas Gandhi. You—or rather, your brain—will enjoy, in parallel, many of the positive attributes and experiences of these people. At the same time, the neuroscientist makes sure that your brain retains your original identity—including all the memories of your lifetime, strung together by your sense of self. Bear in mind that you experience only certain key aspects of these other lives (and your own), as a result of the right pattern of activity having been created in your brain. But none of it exists in the outside world. It’s a delusion of sorts, though one that can’t get you into trouble.
Of course, this is the stuff of science fiction, but in my view the idea hasn’t been taken to its logical conclusion, nor have its philosophical implications been clearly spelled out. It is possible that the neuroscientist cannot accurately preserve every last detail of “you” in your entirety, given the slight changes introduced by the addition of the attributes and experiences of those others. But even if he creates a reasonably good approximation of you, my core argument would still be valid. (After all, you already fluctuate from moment to moment!)
Given a choice, would you choose the vat scenario or be content to remain the “real” you in the real world you live in now? (Assume, for the sake of argument, that the real you is fairly happy and that the chances of eventually dying—or living eternally—are the same, whether you’re in the vat or in the real world.) Ironically, most people I know—even scientists—pick the latter alternative, on the grounds that it is “real.” Yet there is absolutely no rational justification for this choice, because in a sense you already are a brain in a vat—a vat called the cranial vault, nurtured by cerebrospinal fluid and bombarded by photons transmitted via the retina. All I’ve asked you is “Which vat do you want?”—and you have picked the crummy one! (The most original answer came from my colleague Stuart Anstis, who said, “The neuroscientist can leave out Gates, Crick, Spitz, and Gandhi; just Hugh Hefner will do.”)
There’s a sense in which my question poses the ultimate philosophical dilemma. If the logical argument is correct, then the time may come when the world will consist of warehouses full of rows and rows of vats of brains that can be kept alive indefinitely, replete with delightful experiences.
It seems inconceivable that your consciousness and personal memories depend on the actual atoms that now constitute your brain. Surely, they depend entirely on software—that is, the information content. The atoms, after all, are renewed completely every few months, yet you are still “you.” So in some ultimate sense, you could ask whether it matters which software continues in which vat or how it is instantiated. What if the neuroscientist created several vats, with several brains identical to yours, and put them in several vats: Which one is you? Would “you” continue in all of them in parallel? It may well be that our ordinary notions about unity and numerosity—and the corresponding terminology—are hopelessly inadequate in dealing with questions about minds and brains. (Just as our everyday notion of causation breaks down in quantum mechanics.)
This raises an even more enigmatic paradox. From an objective, third-person point of view, there’s nothing special about the information in your brain, whether in your cranium or in a vat, but from your internal perspective it’s everything. The irony is that our brains create an objective science and then proceed to push out subjective experience of the very selves that gave rise to science in the first place! Isn’t something wrong here?
These are brain-boggling conundrums. There is only one argument against the vat scenario that I can think of, but it isn’t really a logical argument: Every human being is different. Each of us is a cultured ape, whose unique mind has been fashioned by the contingent nature of our life experiences derived from the real, external world. The universe is a network of causation, of which you are one insignificant node—yet one that would be hard to replicate. And even if this could be done, would you want it done? What’s so sacred about “real” reality? This is a question that belongs to the realm of philosophy rather than of science. Science can provide data relevant to the vat question, but not its ultimate answer.
I confess that I, too, would pick the “real” me, perhaps because of a foolish sentimental attachment to my present reality, or perhaps because I believe, unconsciously, that there is “something else” after all—something priceless about the here-and-now of conscious experience that we simply don’t understand. As the Bard might have said, if the question had been addressed to him: “To be me, or not to be me: that is the question.”