Tuesday, March 4, 2014

Lucretius, and stories about the Nature of Things

I never took courses in Classics, so my knowledge of the major figures and their works is only sometimes from my own informal reading, and mainly from secondary summaries or hearsay.

But, after having read of and about it for many years, I decided I should actually read Lucretius' (99-55BC) long poem entitled De Rerum Natura (On the Nature of Things).  So many times, I've heard that Lucretius anticipated modern science in sometimes rather eerily prescient ways, and I felt I should see for myself.  I can't read Latin, so I have read an English prose translation in English, hoping at least to see the content, even if unable to appreciate the artistry.  

The deep truths?  Source: crusader.bac.edu

Lucretius was a Roman, nominally writing to persuade a friend of his, but he was basically expounding the views of the Greek Epicurean school of philosophy, led by Epicurius and Democritus and others who lived a couple of hundred years earlier. Among other things, the Epicureans argued persuasively that there were no gods and that human existence is matter-to-matter, dust-to-dust: enjoy life while you have it because that's all there is.  You will decay and your material will return to the cosmos from whence it came.  Nothingness cannot generate material, and material is eternal.  Your mind (or spirit, or whatever term you use) is part of your body and disappears with your body, into the cosmos, to be re-used in the future, as it had come to form you when you were conceived.

There exists matter, they said, made of atoms ('a-tom', or cannot cut), which are the smallest fundamental particles, and 'void' (space).  Atoms move around randomly through space and collide when they meet, at which time they can stick and form larger constructs, which today we call  'molecules'.  Aggregates of these compounds make up the stuff of the world.  It can separate and rejoin, but matter is neither created out of nothing nor destroyed, nor is space.  To allow for our apparent free will, the Epicureans said that atoms could sometimes 'swerve' from their normally determined paths.

The atomic theory of the Epicureans sounds quite like modern molecular and atomic physics and cosmology (though it is true that modern physics does seem to allow strange things like the creation of matter and energy from cosmic vacuum, and perhaps multiple universes, and so on).   Thus, the ideas Lucretius described can seem presciently scientific, two thousand years before their time.  I have read such characterizations frequently.   But there are some interesting points here, that have to do with how ideas are anchored in reality, and with selective reporting.

For one thing, if you read the rest of Lucretius, you'll find stories of the origins of the things in an earth-centered universe, including anthropological tales explaining the origin of humans and their cultural evolution--how we started out crude and beast-like, then discovered weapons, clothing, governments, language and song, the discovery of agriculture, domestication of animals.  He also used his theory to explain the nature of lightning, earthquakes, volcanoes, weather, geology,  gravity,why the Nile floods and the nature of magnetism.  He explained the working of our senses like vision, touch and taste, in atomic terms--accounting, for example, for the emanations from the atoms on the surface of our bodies, that enable us to see 'ourselves' in mirrors.  He raised developmental arguments to show that chimeric beasts, like Centaurs, cannot be real.  He delves into racial variation and why different populations are subject to different diseases.  And he goes into the clinical nature and epidemiology of plagues.

A main aim of Lucretius was to purge people of superstition.  He fervently wanted to dismantle anything other than a pure materialism, even in explaining the origin of moral aspects of society.    In this sense, too, he is favorably cited for his 'prescient' materialistic atomic theory of everything.

In the major sections of De Rerum, however, the apparent prescience becomes less and less, and any idea that he foreshadowed modern science dissolves.  Basically, the Epicureans were applying their notion of common-sense reasoning based on very general observations.  They strung out one categorical assertion after another of what 'must' be the case.  In today's parlance, they were providing hand-waving 'explanations' ('accounts' would be a better term) that seemed consistent but did not require any sort of rigorous means of establishing truth.

Along comes the Enlightenment
Aristotle, Plato, and others of the Greek philosophers reinforced the idea that reasoning itself was enough to generate understanding of the world.  We are basically built, they said, to see and understand truth.  Such a view of knowledge lasted until about 400 years ago, the period called the Enlightenment (in Europe), the time of Francis Bacon, Descartes, Galileo, Newton, and many others.  Those authors asserted that, to the contrary, to understand Nature one had to make systematic observations, and develop proper, formal, systematic reasoning to fit hypotheses to those observations, to develop general theory or laws of the world.  Out of this was born the 'scientific method' and the idea that truth was to be understood by empiricism and actual testing of ideas, not just story-telling--and no mysticism.

Reading Lucretius makes one realize first, that even if a story like the Epicureans' atomic theory has aspects we'd regard today as truth, it was to them basically a sort of guessing.  Secondly, just because a story is plausible does not give it a necessary connection to truth, no matter how consistent the story may seem.  We now do have actual 'scientific' theories to account for--or, now, actually, explain--phenomena such as earthquakes, weather, volcanoes, the nature of metals and water, the diversity of life, a great deal of biology, and even culture history.  If you think of how we know these things, even if there are major gaps in that knowledge, you can see how very powerful and correct (or at least much more accurate) a systematic approach to knowledge can be, when the subject is amenable to such study.

It is a great credit to centuries of insightful, diligent scientists, our forebears, whose legacy has brought us to this point.  It is a wonderful gift from them to our own time.

Advances in technology and methods may be making some Enlightenment concepts obsolete, and we continually find new ways of knowing that go ever farther beyond our own personal biological senses.  For those of us in science, reading the likes of Lucretius is an occasion to compare then and now, to see why just being intelligent and able to construct consistent explanations is not enough, and that for many areas we do now have ways to gain knowledge that has a firmer footing in reality--not just plausibility.

That's all to the good, but if you do a more measured reading of Lucretius, you can see that in many ways we haven't come all that far.  We do a lot of cherry-picking of things in Lucretius that sound similar to today's ideas and thus seem particularly insightful.  But it is not clear that they were more than a mix of subjective insight and, mainly, good guesses--after all, there were competing theories of the nature of Nature even at the time.  And other areas of Epicurean thought, well, are just not mentioned by those remarking on their apparent modernity.  Selective citation gives an impression of deep insight.  Most of De Rerum Natura was simply story-telling.

In many areas of science, perhaps even some aspects of fundamental physics and cosmology, but particularly in the social and even aspects of evolutionary sciences, we still make careers based on plausibility story-telling.  Our use of mathematics or statistical methods--random surveys, questionnaires, arguing by analogy, and so on--and massive data collection, give the same sort of patina of professional wisdom that one can see in the rhetoric of Lucretius.

We tell our stories with confidence, assertions of what 'must' be so, or what is 'obvious'.  Often, those interested in behavior and psychology are committed to purging religious mysticism by showing that behavior may seem immaterial but that this is an illusion, and purely material evolutionary and genetic explanations are offered.  No 'free will'!  The world is only a physical reality.  The role of natural selection and competition in explaining even morality as a material phenomenon is part of this, because Darwin provided a global (may one say 'Epicurean'?) material framework for it.  Evolutionary stories are routinely reported to the public in that way as well.  Even if some caveats or doubts are included here and there, they are often buried by the headlines--and the same can be found in Lucretius, over two thousand years ago.

Explanations of physical and behavioral variation and its evolutionary causes, along with many 'adaptive' stories making forcefully asserted plausibility arguments about what evolved 'for' what, still abound. They are not just told on television--we can't really blame Disney and Discover for appealing to their audiences, because they are businesses; but the same stories are in the science journals and science reportage as well.  We see tales every day reporting miraculous discoveries about genetic causation, for example.  It is sobering to see that, in areas where we don't have a really effective methodology or theoretical basis, we are in roughly similar sandals as our ancient predecessors.

Cherries; Wikipedia
Intoxicated by the many genuinely dramatic discoveries of modern, systematic science, we do our own cherry-picking, and tend to suspend judgment where findings are less secure, dressing our explanations in sophisticated technological hand-waving.

When we don't have actual good explanations, we make up good-sounding stories, just as our forebears did, and they're often widely accepted today--just as they were then.


Holly Dunsworth said...

Too many hypotheses aren't falsifiable and are only thrown out of the professional zeitgeist when better or preferred hypotheses are offered...

Ken Weiss said...

It's true, but worse than that. The reason is that falsifiability is not a good criterion for inference or establishing truth. One can 'falsify' an hypothesis because of bad study design or measurement. Evolution generates differences among individuals, populations, and species, so failure to replicate is not a necessarily a falsification.

Or, many small effects may generate a result and our idea that any one of them we stipulate is involved by the kinds of statistical significance criteria we use, may simply be wrong--the factor may be involved but not enough to be detectable in a given study.

And then there is the Goedel principle that may apply to logical reasoning and empirical work--that there may be truths that our approaches just cannot confirm and we may not be able to know which ones they are.

Sometimes the criterion works, and as you say sometimes more persuasive ideas come along--if we're lucky the successor has better empirical support or, if imperfect, seems at least to be more accurate.

But sometimes it's just story-telling.