Showing posts with label NewScientist at 50. Show all posts
Showing posts with label NewScientist at 50. Show all posts

Nov 28, 2006

NewScientist at 50: Paul Broks on consciousness

Broks gives a whirlwind tour of the last fifty years of neurological research,
a Copernican revolution of the self; a historical shift from the age of solipsism, when we were all at the centre of the universe - self-loving, self-loathing, self-absorbed - to an era of self-dispersion when ego is deemed constrictive. I saw the science of selfhood figure increasingly in the great social and moral debates of the century, from age-old wrangles about euthanasia and free will to disputes over brain enhancement, cyberethics, and the fusion, fission and transposition of minds.
In his most interesting moments, Broks, much like Dr. Oliver Sacks, shows how the brain can break down to reveal its essences.
The neurological diseases that were then still prevalent tended to carve human nature at its joints in such ways, and one occasionally saw what appeared to be clear dissociations of the two "selves". I remember an epileptic patient telling me of her intermittent loss of identity, a condition known as transient epileptic amnesia. Her surroundings would suddenly feel unfamiliar, and then she would begin to feel unfamiliar to herself. Soon she had no idea who she was, where she was or what she was doing. She was stripped to the minimal self: a floating point of subjective awareness untethered by identity.

In other, rare, cases I saw the opposite: the minimal self dissolving, leaving only the story of the extended self. One patient had a strong sense of identity and autobiography but believed that she had ceased to exist. "Am I dead?" she asked. This condition, Cotard's syndrome, was due to a neurological decoupling of feelings and thoughts. Thinking that one exists was not enough: the notion had also to be felt - "I feel I think, therefore I am."
This "dissolution" of the self, in society, in life, in medicine, where does it leave us? Says Brok, "And in the end? A liberating truth. There are no souls, only stories."

Nov 27, 2006

NewScientist at 50: Vlatko Vedral on free will

Face it: we all want to predict the future, and science, with its formulas, emphasis on repeatability, and rigor, offers us our best shot at prognosticating, whether it's the market, the weather, or the next horse race. (Your lacking love life will stay that way, science or no.)

When it comes to predicting human behavior, though, we stumble on severe epistemic roadblocks. Enter Vlatko Vedral, posing a physicist's counterpoint to Patricia Churchland's neurophilosophical musings. Are we free? Vedral concludes[sub req]:
To have the kind of free will we would like involves walking a fine line between determinism and randomness. We must be able to freely make our actions, but they should then result in deterministic (that is, non-random) effects. For example, we may want to be free to send our kids to a school of our choice. But then we also want to believe that the laws of physics (and biology, sociology and so on) ensure that going to a good school is highly likely to lead to a better life. Having free will is pointless without a certain degree of determinism.

The same can be said about studying physics. I want to believe that the choice regarding which aspect of nature I want to study - whether I want to measure the position or velocity of a particle, for example - lies with me. But what I also want is some degree of deterministic behaviour in nature that would then permit me to infer laws of physics from any measurement that I choose to make. In fact, the only means we have for deducing the basic equations of quantum mechanics means that they are fully deterministic, just like those of Newtonian mechanics.

There is nothing mysterious or controversial about this, but look what happens when we apply this to ourselves. If we are all made up of atoms, and if atoms behave deterministically, then we too must be fully determined. We simply must share the same fate as the rest of the universe. When we look inside our brains, all we find are interconnected neurons, whose behaviour in turn is governed by their underlying molecular structure, which in turn is fully governed by the strict laws of quantum mechanics. Taking the argument to extremes, the laws of quantum mechanics ultimately determine how I deduce the laws of quantum mechanics, which appears to be a fully circular argument and therefore logically difficult to sustain....

The most honest position for a scientist on the question of free will is definitely agnostic: I simply do not know. What I do know is that when I was asked to write about free will as a physicist I found the idea so exciting that I had no choice but to agree to take it on.
I disagree with Vedral's psychology of choice: we don't have to be sure that our actions will bring happy results, but just confident that our chances are good.

Nov 25, 2006

NewScientist at 50: Patricia Churchland on free will

NewScientist often features humorous little pieces on "nominative determinism," the idea that your name can control your destiny.

It's not quite perfect. Consider Patricia Churchland, a neurophilosopher who isn't exactly friendly to a theistic worldview, since she espouses "eliminative materialism," the idea that the mind is matter, and that's all that matters.

In her contribution to NewScientist's 50th anniversary special, she explains how this affects traditional notions of free will. She begins by asking us to consider a tumor that turns an otherwise normal man into a pedophile: not just a hypothetical, but as reported in a 2003 article from the Archives of Neurology.
A middle-aged Virginian man with no history of any misdemeanour began to stash child pornography and sexually molest his 8-year-old stepdaughter. Placed in the court system, his sexual behaviour became increasingly compulsive. Eventually, after repeatedly complaining of headaches and vertigo, he was sent for a brain scan. It showed a large but benign tumour in the frontal area of his brain, invading the septum and hypothalmus - regions known to regulate sexual behaviour.

After removal of the tumour, his sexual interests returned to normal. Months later, his sexual focus on young girls rekindled, and a new scan revealed that bits of tissue missed in the surgery had grown into a sizeable tumour. Surgery once again restored his behavioural profile to "normal".
Churchland uses this extreme case to test the limits of the libertarian conception of uncaused free will, which she ultimately dismisses, writing,
...choices are made by brains, and brains operate causally; that is, they go from one state to the next as a function of antecedent conditions. Moreover, though brains make decisions, there is no discrete brain structure or neural network which qualifies as "the will" let alone a neural structure operating in a causal vacuum. The unavoidable conclusion is that a philosophy dedicated to uncaused choice is as unrealistic as a philosophy dedicated to a flat Earth.
Instead, Churchland advocates a framework of moral responsibility based on "self-control."
Unlike free will, self-control is a concept that we can usefully apply to other animals.... Through reinforcement, my dog has learned to lie quietly when the local squirrel taps the screen door for peanuts; a hungry chimpanzee will reach for a banana only if he knows the alpha male cannot see it, but will suppress the desire otherwise. Ulysses famously bound himself to the mast of his ship to avoid seduction by the sirens...

Self-control also allows us to make sense of difficult cases where free will is unhelpful....

...[E]ventually we will understand, at least in general terms, the neurobiological profile of a brain that has normal levels of control, and how it differs from a brain that has compromised control.
In other words, retributive justice can operate without a traditional view of totally free choice. We use the apparatus of the state to limit those who can't limit themselves. (Hobbes would proud.)

Lastly, Churchland answers those who criticize reductionism from aesthetic grounds.
In essence, the self is a construction of the brain; a real, but brain-dependent organisational network for monitoring body states, setting priorities and, within the brain itself, creating the separation between inner world and outer world....

Is one cheapened by this neuroscientific knowledge? I think not. Self-esteem and self-worth are wholly compatible with realising that brains make us what we are.... [T]he beauty, intricacy and sophistication of the neurobiological machine that makes me "me" is vastly more fascinating and infinitely more awesome than the philosophical conception of the brain-free soul that somehow, despite the laws of physics, exercises its free will in a causal vacuum. Each of us is a work of art, sculpted first by evolution, and second by experience in the world. With experience and reflection one's social perception matures, and so also does the level of autonomy. Aristotle called it wisdom.

Nov 20, 2006

NewScientist at 50: Robert Hazen defines life

What is life? Short answer: "Life is a self-sustained chemical system capable of undergoing Darwinian evolution," as Gerald Joyce puts it. For the long answer, we turn to Robert Hazen [sub. req.]
Any attempt to formulate an absolute definition that distinguishes between life and non-life represents a similar false dichotomy. The first cell did not just appear, fully formed. Rather, life must have arisen through a sequence of emergent events - diverse processes of organic synthesis followed by molecular selection, concentration, encapsulation and organisation into various molecular structures. The emergence of self-replicating molecules of increasing complexity and mutability led to molecular evolution through the process of natural selection, driven by competition for limited raw materials.

What today appears as a yawning divide between non-life and life obscures the fact that the chemical evolution of life occurred in this stepwise sequence of successively more complex stages. When cells emerged, they quickly consumed virtually all traces of the earlier stages of chemical evolution. "Protolife", a rich source of food, was wiped clean by voracious cellular life.

Our challenge, then, rather than to define life in absolute terms, is to establish a progressive hierarchy of steps leading from a prebiotic Earth enriched in organic molecules to cellular life. The nature and sequence of these steps may vary in different environments, and we may never know the exact sequence - or sequences - that occurred on Earth. Yet many of us suspect that the chemical path has a similar, inexorable direction on any habitable planet or moon.
I appreciate Hazen's distinction between top-down and bottom-up attempts to work out a definition, and agree that our current conception of life is too advanced for us to likely ever know what came before.

Elsewhere (subscribe already!) Hazen notes that the short definition is pragmatic and defensible, since it would exclude "artificial" (read: digital or virtual) lifeforms. However, here's where blurs begin again. What happens when computers, a la The Terminator, take control of material resources and begin replicating? It's only a matter of time.