William H. Calvin, A Brain for All Seasons: Human Evolution and Abrupt Climate Change (University of Chicago Press, 2002). See also http://WilliamCalvin.com/BrainForAllSeasons/chunnel.htm.
ISBN 0-226-09201-1 (cloth) GN21.xxx0
Available from amazon.com or University of Chicago Press.
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William H. Calvin
University of Washington
the fossils at eighty miles per hour, I can’t see a thing except for
some little lights that go by every two seconds, serving to reassure
you that the train hasn’t stopped somewhere beneath the ocean. A train usually jerks around enough to reassure the
passengers that it hasn’t stopped, but this undersea railroad is
pretty smooth. I’m en
route to a meeting in Paris, so you get my third installment for our
virtual seminar from a tunnel (“the chunnel”) that is 40 meters
beneath the English Channel connecting Folkestone, England, with
Thinking back to the Sand Walk, I now realize that we often make
mistakes in science by making logical but erroneous extrapolations.
For example, “It’s just a drop in the ocean” doesn’t
always scale up. We assume
that oceans mix and dilute anything added, despite the evidence that
oceans stay poorly mixed (and thus stay cold in the depths) because of
dynamic processes that circulate in “streams” more quickly than
diffusion can be effective. This
is of some importance; were the depths to start warming up, CO2
would come bubbling out just like from an uncapped bottle of seltzer.
It would, of course, add to the greenhouse effect.
We don’t scale up time very well either, which is why Darwin
and the geologists of the nineteenth century had such a problem
convincing nonscientists about the time scale of evolution.
And they worked so hard in selling gradualism over eons that
today, when we first begin to think about evolutionary change, we often
assume that it is just like when you slide a cardboard box down a
loading ramp. It doesn’t
accelerate very much by the time it reaches the bottom; it’s not too
different from pushing it across a horizontal floor.
But every beginning physics student soon learns how different
fast dynamics is from slow statics.
Process becomes important and oscillations may occur, as when a
pendulum converts kinetic and potential energy back and forth.
In nonlinear systems, dynamics is further complicated because
there are often modes of operation, with change-of-state transitions
between them that require a story of their own.
The latent heats of the solid-liquid-vapor transitions are the
best known – and appearances can fool you.
A cloud layer on the lee side of a mountain may look perfectly
static, but it is really forming by condensation at the bottom (which
heats the water droplets) and evaporation at the top (which cools
them), with a constant flow of water up through the cloud.
The cloud is just an emergent property, its thickness a
consequence of those change-of-state transitions.
For a century, we tried to pretend that evolutionary transitions
were just like that box slowly sliding down a ramp, where a slight
imbalance of forces operated slowly.
But change-of-state transitions may become far more important
than the longer-lasting states. For
example, animals must survive and reproduce during a chaotic climate
transition, when all of their hard-earned efficiency adaptations to a
particular environment have just become worthless and a new regime
hasn’t yet been established.
we’ve popped out into France in a mere twenty minutes.
Farther up the French coast is one of the German V-2
rocket-launching sites, made into a museum explaining how Hitler
planned to invade Britain. Apropos
of whether scientists are seen as saviors or serpents, I am reminded of
Tom Lehrer’s famous satire on scientific responsibility, “Once the
rockets are up / Who cares where they come down? / That’s not my
department / Says Wernher von Braun.”
This part of France looks suspiciously like Kansas – I
confess, I graduated from a Kansas high school, and learned my
evolution later. Hereabouts, the farm buildings have nice red tile roofs.
Improbably, there are two-story-high earthen berms along the
railroad’s right-of-way wherever there is a nearby barn.
These artificial hills deflect noise upward, perhaps keeping the
cows from being disturbed by the noise of the Eurostar trains.
I’ll get to ancient climate presently, but first I thought
that I’d do a little stage-setting for this virtual seminar, a
shopping list of desiderata.
Since I don’t want you to get too focused on higher
intellectual functions (skimming the cream is, in general, a bad
habit), this will be a short list of all the major behavioral changes
since our last common ancestor with the chimps and bonobos, 5-6 million
Mine are all major improvements that need an evolutionary
explanation for how we got beyond a great-ape level of abilities in so
short a time. They are
things like extensive altruism – not just the sharing with
relatives that genes-in-common can help explain, but the sharing with
(and taking risks to come to the aid of) strangers, where the giver
gets paid back (if at all) by some third person.
Also, things that develop trust among individuals in large
groups who don’t all know one another – a prime example is the
worldwide scientific community.
and cooperation may be good for the species in the long run, but
evolution has no known foresight mechanism.
This means that every little increment has to pay its own way
with immediate advantages. It’s
difficult even to explain an in-between stage, reciprocal altruism –
that’s where you’re doing favors for unrelated friends – because
the entry-level stages of it are so easily swamped by freeloaders who
receive without giving back. It’s
leaky, like a tire that sinks after a while.
Yet some reciprocal altruism exists, in chimps and bonobos,
and our ancestors developed altruism more generally into
disaster relief, welfare, and peacekeeping forces.
How was such altruism bootstrapped up, through a series of
stages with intermediate payoffs?
Similar questions apply to other beyond-the-apes abilities that
we have. Yet, compared to
stones and bones, such issues can be confusingly abstract, and so we
tend to focus on “hard evidence” like the hip-and-knee
rearrangements needed for upright posture.
Or the big increase in brain size.
We can, however, infer a lot of behavioral changes, just by
comparing our fully-human abilities with the versions seen in our
So here’s my most recent attempt at a hominid bootstrap list,
for what happened along with upright stance and enlarged brains. In my opinion, the big beyond-the-chimps improvements that
need step-by-step bootstrap explanations covering the last five million
altruism (beyond chimp-level reciprocal altruism),
accurate throwing (not just flinging, which many chimps
do, but practicing to hit smaller and smaller targets),
extensive tool making (especially tools with which to
make other tools),
protolanguage (real words used in short combinations,
such as the language of two-year-olds),
structured language (long sentences with recursive
embedding of phrases and clauses, likely a different evolutionary
planning for uncertain futures (not just the seasons) and
their associated agendas,
logical trains of inference that allow us to connect
remote causes with present effects (and a propensity to guess at them,
useful both for doing science and for fooling yourself),
ethics (which may require an ability to estimate the
consequences of a proposed course of action, and judge it from
concealed ovulation (the disappearance of obvious “in
heat” periods tended to force males into prolonged sharing with a
female and her previous offspring, just to be around at the right
games with made-up
rules (hopscotch, not just play) and dance,
our fascination with discovering hidden patterns, seen in music
(not just rhythm but four-part harmony), art and abstractions,
crossword puzzles, and doing science, and
our extensive offline creativity (an ability to
speculate, to shape up quality by bootstrapping from rude beginnings,
yet without acting in the real world).
notice that I didn’t use the C word here, though I did describe most
of the beyond-the-apes uses of consciousness along the way.
There are many more differences, of course, but I’m trying
here for ones with a big order-of-magnitude improvement beyond great
ape abilities, the ones which will surely play some prime-mover or
hitchhiker role in the evolutionary scenarios that we try to construct
for the last five million years. (Such
“uniquely human” lists have proved very useful in the past –
because they stimulate ape researchers to disprove them!)
This isn’t, by the way, a list of “important” things. For example, dozens of fine primate studies over the last few
decades have shown that we share a lot of social behaviors with chimps
and bonobos (who have an amazing amount of hugging and kissing,
reassuring touches, coalition behaviors, and so forth).
These would make everyone’s list of “important” attributes
– and, forty years ago, such things would have made my
up-from-the-apes list. They’re
obviously important to “being human” but – as it now turns out
– they may not be
order-of-magnitude advances beyond those of five million years ago.
My list is a differential view (as it were, subtracting apes
from humans), not the grand view.
Yes, that’s a rather concentrated list, rather like a
five-course French dinner stuffed into a small take-out box.
My sympathies. But
you get a week to dissect and digest it while I soak up some more
linguistics and archaeology in a dim classroom in Paris, the variety
with hard seats to keep the students awake.
You can argue among yourselves about possible additions to, and
subtractions from, my list. It’s
a game anyone can play.
minutes ago, we were in farmland, and I was puzzled at why the
other passengers were putting their coats on.
Well, I just looked up again and I don’t think we’re in
Kansas anymore. That’s
Paris out there. The
Eurostar train isn’t that fast.
It’s just that France has some well-delineated urban areas
that lack the usual sprawl of many other cities, the strips extending
from the core along the traffic arterials, so like the way that
invasive cancers spread along arteries, veins, and nerves.
The French, at least in places, have learned to deal with that urban form of cancer. Maybe they will build berms someday to protect people in the cities from the train’s noise, now that they have set a precedent with consideration for the cows.
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