Claim CG041:
Standard science says that humans lived as hunter-gatherers for 185,000
years before discovering agriculture less than 10,000 years ago. It is
improbable that the Stone Age men, who were as intelligent as we are, did
not discover how to plant food plants for so long.
Source:
Humphreys, D. Russell. 2005. Evidence for a young world. Impact 384
(June): v-vi.
Response:
- Why is it implausible that humans lived for a long time without
agriculture? Agriculture allows higher population densities, but it
leads to an overall decrease in the quality of life over that of
hunter-gatherers (Diamond 1987). In particular, agriculture requires
much more work for a lower quality, less dependable diet, and it
increases disease. There was no pressing reason to adopt agriculture
in the first place.
- The end of the last ice age about 10,000 years ago may have facilitated
the origin of agriculture at that time. The changed climate may have
made agriculture possible in more areas, and/or it may have led to a
human population increase which required agriculture to sustain.
- It is possible that agriculture has been discovered several
different
times over the last 180,000 years. Climate change, even over
relatively short periods of a few decades, has caused the collapse of
agricultural societies in historical times, and the climate has changed
dramatically over the last 180,000 years. Agriculture in the distant
past may have been lost repeatedly.
- The assumption that humans have not changed in intelligence over the
past 185,000 years is unsupportable and many not be true. A team
of geneticists has found evidence that human brains have evolved
adaptively recently (and may still be evolving). Two genes associated
with brain size have genetic variants whose high frequencies indicate
that they spread under strong positive selection. A haplotype (genetic
variant) of the Microcephalin gene arose about 37,000 years ago (95
percent confidence interval of 14,000 to 60,000 years) (Evans et
al. 2005). An ASPM haplotype arose only about 5800 years ago (95
percent confidence interval of 500 to 14,000 years) (Mekel-Bobrov et
al. 2005). It should be emphasized that the effects of these
haplotypes is currently unknown; the evidence for strong selection
indicates only that their effects are important, that humans have
evolved recently in some way. It may be significant that they occurred
around the same times as the introduction of modern humans to Europe
and the origins of art (about 40,000 years ago) and the rise of
agriculture and writing (about 10,000 to 6,000 years ago). It is also
possible that these genes are not relevant to the origins of
agriculture but others are. The larger point is that there is evidence
that humans continue to evolve in subtle ways.
- Regardless of whether we know why more technological progress was not
made earlier, humans do have a long record, stretching back much, much
farther than 6000 years, and we do have good indications of levels of
technology during this history. "I do not know why this happened" does
not lead logically to "this did not happen."
References:
- Diamond, Jared. 1987. The worst mistake in the history of the human
race. Discover, May: 64-66.
http://anthropology.lbcc.edu/handoutsdocs/mistake.pdf
- Evans, Patrick D. et al. 2005. Microcephalin, a gene regulating
brain size, continues to evolve adaptively in humans. Science 309:
1717-1720.
- Mekel-Bobrov, Nitzan et al. 2005. Ongoing adaptive evolution of
ASPM, a brain size determinant in Homo sapiens.
Science 309:
1720-1722.
Further Reading:
Diamond, Jared. 1997. Guns, Germs, and Steel: The Fates of Human
Societies. New York: Norton.
created 2005-9-23