Thursday, June 30, 2011

Consciousness - correlation is not a cause

Here are excerpts from Susan Blackmore's contribution to the question "What scientific concept would improve everybody's cognitive toolkit?"
The phrase "correlation is not a cause" (CINAC) may be familiar to every scientist but has not found its way into everyday language, even though critical thinking and scientific understanding would improve if more people had this simple reminder in their mental toolkit.

One reason for this lack is that CINAC can be surprisingly difficult to grasp. I learned just how difficult when teaching experimental design to nurses, physiotherapists and other assorted groups. They usually understood my favourite example: imagine you are watching at a railway station. More and more people arrive until the platform is crowded, and then — hey presto — along comes a train. Did the people cause the train to arrive (A causes B)? Did the train cause the people to arrive (B causes A)? No, they both depended on a railway timetable (C caused both A and B).

Stories of health scares and psychic claims may get people's attention but understanding that a correlation is not a cause could raise levels of debate over some of today's most pressing scientific issues. For example, we know that global temperature rise correlates with increasing levels of atmospheric carbon dioxide but why? Thinking Cinacally means asking which variable causes which or whether something else causes both, with important consequences for social action and the future of life on earth.

Some say that the greatest mystery facing science is the nature of consciousness. We seem to be independent selves having consciousness and free will, and yet the more we understand how the brain works, the less room there seems to be for consciousness to do anything. A popular way of trying to solve the mystery is the hunt for the "neural correlates of consciousness". For example, we know that brain activity in parts of the motor cortex and frontal lobes correlates with conscious decisions to act. But do our conscious decisions cause the brain activity, does the brain activity cause our decisions, or are both caused by something else?

The fourth possibility is that brain activity and conscious experiences are really the same thing, just as light turned out not to be caused by electromagnetic radiation but to be electromagnetic radiation, or heat turned out to be the movement of molecules in a fluid. At the moment we have no inkling of how consciousness could be brain activity but my guess is that it will turn out that way. Once we clear away some of our delusions about the nature of our own minds, we may finally see why there is no deep mystery and our conscious experiences simply are what is going on inside our brains. If this is right then there are no neural correlates of consciousness. But whether it is or not, remembering CINAC and working slowly from correlations to causes is likely to be how this mystery is finally solved.


  1. Anonymous4:47 AM

    Susan *Blackmore*

  2. Anonymous5:57 AM

    If we have no inkling about what the solution could be, what inclines you to have that guess?

    Actually confronting phenomenal experience to brain states leads to a very different guess, I guess.

  3. Yes, Sue is right - we have to get out of the delusions about our mind. Quoting: "Once we clear away some of our delusions about the nature of our own minds, we may finally see why there is no deep mystery and our conscious experiences simply are what is going on inside our brains."

    I do not know why in the world we give so much importance to a "mind." Why cannot we think of it as another organ, a part of the body-organism, as much as a stomach or heart is? All these body parts (including a mind as activity of brain) are there to protect and perpetuate the species. Some ancient philosophers even thought of mysterious mental worlds and mental bodies and mind-stuff with which minds are made! We know very well now that all of those things a mind is supposed to be is seen as em-chem changes in the brain.

    The next important point is not a question about which causes which but whether we do find a foot-print of consciousness in the activity of neuronal other cells of the brain.

  4. One interesting (off topic) thing about CINAC thinking is that it breaks down in basic physics. We think of causation with an implicit forwards time direction, for example, we wouldn't say that eating a cake tomorrow can't cause it to be baked yesterday.

    However, this asymmetry of time doesn't apply at the particle level where interactions are symmetric in time. An electron accelerates sideways when it absorbs a photon; later it might emit a photon and accelerates the other way, just like rolling the film backwards. When we speak of cause and effect and assume that time runs only one way but at the micro level since interactions are symmetric, causality itself becomes hard to pin down.

    At the macro level things don't work like that: shattered vases don't unshatter. Heat always flows from hot to cold. Even though many individual particle collisions will transfer energy against the gradient, the net effect over zillions of of interactions is for heat - molecular kinetic energy - to always flow down the gradient.

    Some physicist have looked to the micro level symmetry for an explanation of entanglement ("spooky action at a distance") where two particles interact then move apart with some indeterminate properties. When a property is measured on one particle a corresponding property is instantaneously changed on the other particle even though the particles may have moved a long way apart, ie, without any possiblity of normal information exchange. A mooted explanation is for the "cause" to propagate backwards in time from the measured particle to the original interaction then forwards to the second particle. This contradict our intuitions of causes occurring before their effect but this may be ok since our idea of cause and effect is generated in our macro stucture, based on the intuitions gained from in the macro world where time "flows", and only one way.

  5. "our conscious experiences simply are what is going on inside our brains." I reckon it's our cells too.