Map of life expectancy at birth from Global Education Project.

Saturday, November 30, 2019

Science and The People

I actually find it pretty easy to understand why many people reject science that conflicts with their religious beliefs. One obvious reason is that membership in most religious communities requires accepting, or at least pretending to accept, certain factual propositions. Community membership is valuable to people, emotionally and in many situations for practical and material reasons. It's hard, and for many people impossible, to walk away from kith and kin.

But there is also a deeper reason. The universe discovered by physicists and the sub-discipline of cosmology is grant, wonderful and astonishing but also very cold and lonely. It makes of humanity a trivial accident. We don't mean shit to anybody but ourselves. That we can make meaning in our own right, that we matter to each other, is the essence of humanism, but that isn't good enough for lots of people. They need the consolation of a caring universe. Alongside this is the fear of death and inability to accept it.

Then there's the third reason. Almost nobody actually understands the cosmologists' universe, how they figured it out and why they are so certain of their conclusions. I have a somewhat better idea than most because I've had a subscription to Scientific American since I was 13 but I actually have never taken a physics course, let alone studied cosmology. Basically it all started when Edwin Hubble discovered that the nebulae are actually entire galaxies in their own right, that the ones that aren't so close as to be bound to ours gravitationally are all receding, and that the farther away they are, the faster they are running away. No, that doesn't put us at the center. It would look the same no matter where you were, no matter what galaxy you were in, because the universe is expanding. So they imagined running the movie backwards and realized that at some point it must have been extremely compact. Maybe infinitely dense and infinitesimal. That would have been about 13.8 billion years ago. (Estimates have varied a bit over time but that's where we are now.)

There is plenty of evidence that this really happened, that for some reason -- of which we have not the slightest idea -- at that time it started expanding and eventually evolved into what we see now. I won't go into more detail but you can read books about it. Hawking's Brief History of Time still stands up pretty well but problems have arisen since then, some of the most difficult of his own making. Cosmologists thought they were getting everything figured out, then they discovered that the expansion of the universe is accelerating, for completely unknown reasons; that most of the mass in the universe consists of something that does not interact with matter in any way except by gravity; and when Hawking figured out that Black Holes evaporate, he created a whole new paradox which you can read about at the link but which you won't really understand very well.

Physicists have a complicated understanding of the universe, based on mathematical structures that predict the outcome of experiments or correspond to observations. I won't even discuss quantum theory but the black hole paradox is enough to get the idea across. It's true in a way that doesn't correspond to our everyday understanding of truth. It's about entities that nobody can see, distances that are incredibly small or incredibly large, time intervals equally infinitesimal and vast. For example, physicists believe that this is the smallest possible distance:

It's called the Planck length. It's about 1/100,000,000,000,000,000,000 the diameter of a proton. If you've been reading the Bible with me you know it's ridiculous, but unfortunately I think the average person, if presented with basic ideas of physics and cosmology, would find them more ridiculous than Noah's Ark. It takes a lot of effort to understand all, or really any of this. Faith is just easier.

Wednesday, November 27, 2019

Not Stayin' Alive

This is not new news, but it's strong confirmation of earlier observations that have been somewhat controversial, and also bad news that the trend is continuing. That trend is declining life expectancy in the U.S. I'm not linking to the full report in JAMA because it's incredibly wonky and behind a paywall anyway, but rather to the associated editorial, which tells you what you need to know.

Before we get into the substance of this, let me explain the concept of life expectancy. I'll try to put this simply, but some people find it confusing. It's really a fictitious, though useful, construct. It isn't really a prediction of the future, but it tells us something about the present. Below is a portion of what's called a "life table." It shows the proportion of people in the U.S. who died in each 1-year age cohort in 2015.

As you can see, .006383, or a little more than 6/1,000 male babies died before their first birthday. (A simplifying assumption is that all deaths occur on June 30. Don't worry about it.) Of the remaining male babies, .000453, which only 4/5 out of 10,000, died before their second birthday. So it's somewhat dangerous to be an infant but once you get past that you're in pretty good shape until you get old. It isn't until age 81 that the probability of death for men goes up to the same level as the infant mortality rate.

So life expectancy at birth is the average (mean) age you would live if you were born in 2015 and experience the same probability of death each year as people who are alive in 2015, i.e. assuming nothing changes in the next 81 years or so. That obviously isn't very likely, so as I say, this is a fictitious concept; it's about the present, not the future. You might also notice that half the men are still alive at age 80 but male life expectancy in 2015 was actually a bit lower than that because that 50% represents the median, and as I say, life expectancy is presented as the mean, which was actually 76.4.* You will also notice that women live longer than men. Life expectancy for Black people of both sexes is lower than that for white people, but black women still live longer than white men.

Okay, so as the linked editorial explains, the decline, which began in 2014 but  followed an earlier plateau, is largely traceable to increased death rates for people in mid-life -- age 25-64, who during the post-war years had been quite unlikely to die. The increased death rate in those years is attributable largely to opioid overdose, alcoholism, and suicide, but not entirely. Obesity-related diseases also contribute. The industrial Midwest, Appalachia, and Northern New England were worst-affected, as were rural vs. urban areas.

Many people are labeling these "deaths of despair," and arguing that they are linked to the economic and social disruption associated with deindustrialization and the declining rural economy. That may be so, although the opioid epidemic is a more equal opportunity phenomenon. How the pain of these places has translated into changing political loyalties, however, is harder to explain. One thing is for sure -- it is not caused by immigration. It also is not caused by abortion, gay marriage, transgendered people, increasing numbers of minority elected officials, or gun safety legislation. I get that people and communities are hurting, but I don't know get why their anger is so misdirected.

* The relatively large number of people who die in infancy drags the mean down more than the small number of very long-lived people pulls it up. This will make sense to you if you have studied statistics, otherwise don't worry about it.