Causality becomes increasingly elusive

Espen sez, "This is an excellent essay by Jonah Lehrer on the increasing difficulty of finding direct causation in medical (or, indeed, all) research. Highly readable, though I would have liked to see a little more about how to address this problem (i.e., with network analysis tools)."

David Hume referred to causality as “the cement of the universe.” He was being ironic, since he knew that this so-called cement was a hallucination, a tale we tell ourselves to make sense of events and observations. No matter how precisely we knew a given system, Hume realized, its underlying causes would always remain mysterious, shadowed by error bars and uncertainty. Although the scientific process tries to makes sense of problems by isolating every variable—imagining a blood vessel, say, if HDL alone were raised—reality doesn’t work like that. Instead, we live in a world in which everything is knotted together, an impregnable tangle of causes and effects. Even when a system is dissected into its basic parts, those parts are still influenced by a whirligig of forces we can’t understand or haven’t considered or don’t think matter. Hamlet was right: There really are more things in heaven and Earth than are dreamt of in our philosophy.

This doesn’t mean that nothing can be known or that every causal story is equally problematic. Some explanations clearly work better than others, which is why, thanks largely to improvements in public health, the average lifespan in the developed world continues to increase. (According to the Centers for Disease Control and Prevention, things like clean water and improved sanitation—and not necessarily advances in medical technology—accounted for at least 25 of the more than 30 years added to the lifespan of Americans during the 20th century.) Although our reliance on statistical correlations has strict constraints—which limit modern research—those correlations have still managed to identify many essential risk factors, such as smoking and bad diets.

Trials and Errors: Why Science Is Failing Us

• [Jerril]

  The big “problem” is that most, if not all, of the “easy-to-spot” causes have been found in the last 150 years or so. We’ve picked off the low hanging fruit, and to stretch the metaphor we’ve made decent inroads into things we can reach by jumping up and down, too.

  But sooner or later we’re going to have to find a way to reach the things that aren’t so easy to pin down – and that’s probably going to have be different from the way we found the easy-to-spot things. To drag that metaphor out again, we’re going to have to invent ladders, or get sticks and knock down the high ones, or train monkeys, or shake the tree, or fly in from the top… or something.

• [Nadreck]

  I don’t believe in all this public health stuff, that says that things like smoking is bad for you.  It’s all based on computer models that can’t even predict exactly who exactly is going to die tomorrow so how can they predict how many people are going to die years from now?  

  Oh, wait, this isn’t a thread on Global Warming?  Never mind.

• [Yacko]

  Quantum computing will illuminate all problems…and then some.

  • [Lobster]

    Well, it will and it won’t.

    • [Mujokan]

      It’ll be a superposition of “will” and “won’t” that collapses into “won’t” due to uncontrolled  decoherence :)

      • [Lobster]

        I hate it when that happens.  Ever try to get decoherence out of a rug?  Schroedinger should have housebroken that cat of his.

• [Mujokan]

  Not much point bringing Hume into this discussion. His was a fairly typical “old philosophy” problem of thinking that concepts or entities described in language must have some kind of absolute, objective reality.  “X reliably precedes Y, but that can never be a matter of deduction, just induction” — it’s a problem that’s not really a problem, due to thinking logic should trump reality, rather than being a simplified description of how probability tends to flow in the real world. I for one can’t imagine what the counterfactual would be like!  Reliably identifying causation can be very difficult, but it’s not really a philosophical problem any longer IMO.

• [noen]

  It gets worse kiddies — “How the Laws of Physics Lie” by Nancy Cartwright

  “the author argues that fundamental explanatory laws, the deepest and most admired successes of modern physics, do not in fact describe regularities that exist in nature [...] that theoretical entities, and the complex and localized laws that describe them, can be interpreted realistically, but the simple unifying laws of basic theory cannot.”

• [jimmoffet]

  Ultimately, we need to get better at approximating complex outcomes. I hate to be in the processing-power-worshipping camp, but it seems like that, and to a lesser extent, more sensitive data collection, is what’s really standing in our way.

  We can’t simply theorize our way to accurately approximated outcomes in all very complex systems. So, sometimes we need lots of data and the processing power to reverse engineer the outcomes. It’s going to be a while, but once we have data collection that can reliably record the movements of (all of) our molecules, along with their states (and we’re closer to this than we are to having the processing power to deal with it…), we can start creating full-scale virtual models of ourselves and start deducing the laws that govern us from macro in, instead of from the micro out.

  You have to let the computer create it’s own rules for interaction between our constituent parts and let it disregard each set of rules when its resultant outcome doesn’t closely match the actual data. After some (less than infinite) amount of time, you should have a set of rules that allows you to test hypotheses on your virtual person with a high degree of certainty.

  The trick is using our clever human brains to rule out large swaths of what would be wasted processing time, so that the amount of time it takes to get there is closer to now than never for any given amount of available processing power. Perhaps by the time the data collection gets sensitive enough, distributed quantum/optic computing will afford our medical labs the luxury of identifying these rules by brute force, but I doubt it.

  It’s actually kind of ironic that you need such fine microscopic detail to start getting a clear picture of the how our macro systems work, but such is sometimes the nature of very complex systems.

  • [AnthonyC]

    There is a very real, very important ethical conundrum with your proposal. At some point when you create a model of a person with sufficient detail, subject to sufficiently accurate simulation (which is your goal), your model isn’t just a model- it is a person, enough like you or me to count as a person, with all the rights and ethical restrictions that implies. It would be as unethical to experiment on such a being as it would be to experiment on you without consent.

• [TimRowledge]

  Hamlet was right: There really are more things in heaven and Earth than are dreamt of in our philosophy.

  Anyone that truly believes that is a bit behind the times on both science and philosophy. They’ve got a tad more extensive since Shakespeare’s maid’s dog-groomer’s brother’s employer wrote Hamlet.

  • [eyebeam]

    No, that’s still true, and always will be.

• [Dmitri DB]

  Stuart Kauffman has some cool ideas that could go for more rep:

  http://edge.org/3rd_culture/kauffman06/kauffman06_index.html
  http://books.google.ca/books/about/Reinventing_the_sacred.html?id=6OcoAQAAIAAJ&redir_esc=y

  As does Monica Anderson:

  http://hplusmagazine.com/2011/03/31/reduction-considered-harmful/
  http://artificial-intuition.com/index.html