Principles of Geology: being an attempt to
explain the former changes of the Earth's
surface, by reference to causes now in operation
is a book by the Scottish geologist Charles
Lyell that was first published in 3 volumes
from 1830–1833.
Lyell used the theory of Uniformitarianism
to describe how the Earth's surface was changing
over time.
This theory was in direct contrast to the
geological theory of Catastrophism.
Many individuals believed in catastrophism
to allow room for religious beliefs.
For example, Noah's Flood could be described
thus as a real geological event as catastrophism
describes the changing of the Earth surface
as one-time, violent events.
Lyell challenged the believers of the catastrophic
theory by studying Mount Etna in Sicily and
describing the changes from one stratum to
another and the fossil records within the
rocks to prove that slow, gradual changes
were the cause of the ever-changing Earth's
surface.
Lyell used geological proof to determine that
the Earth was older than 6,000 years, as had
been previously contested.
The book shows that the processes that are
occurring in the present are the same processes
that occurred in the past.
== Book ==
Published in three volumes in 1830–33, the
book established Lyell's credentials as an
important geological theorist and popularized
the doctrine of uniformitarianism (first suggested
by James Hutton in Theory of the Earth published
in 1795).
The central argument in Principles was that
"the present is the key to the past": that
geological remains from the distant past could,
and should, be explained by reference to geological
processes now in operation and thus directly
observable.
The book is notable for being one of the first
to use the term "evolution" in the context
of biological speciation.In Lyell's work,
he described the three rules he believes to
cause the steady change of the Earth.
The first rule is that geologic change comes
from slow and continual procedures that have
been happening over a long period of time.
This rule is the basic ideal of Uniformitarianism
and is easy to understand why this was a rule.
The second rule is that all the forces that
affect the geology of the Earth comes from
the Earth.
The third rule is that celestial cycles do
not impact the patterns of Earth's geologic
record.
Rule two and rule three go together because
Lyell thought that only forces on the Earth
cause changes to Earth's geology, and nothing
else.
Volume 1 introduces Lyell's theory of uniformitarianism.
He develops and argues that the earthly processes
that we see in the present were the same processes
as in the past and caused the Earth to look
like it does today.
Volume 2 builds off of the uniformitarianism
theory in volume 1, but focuses more on the
organic matter rather than the inorganic matter.
This volume is what Darwin took with him on
his voyage on the Beagle.
In the 3rd volume, Lyell identifies four periods
of the Tertiary: Newer Pliocene, Older Pliocene,
Miocene, and the Eocene.
Lyell used deposits and fossils from these
periods to argue for uniformity during the
Tertiary.
This also talks about the grammar or syntax
of the processes that occurred in the past
in today's language.
== Influence ==
Lyell's interpretation of geologic change
as the steady accumulation of minute changes
over enormously long spans of time, a central
theme in the Principles, influenced the 22-year-old
Charles Darwin, who was given Volume 1 of
the first edition by Robert FitzRoy, captain
of HMS Beagle, just before they set out (December
1831) on their voyage on the Beagle.
On their first stop ashore at St Jago, Darwin
found rock formations which -seen "through
Lyell's eyes"- gave him a revolutionary insight
into the geological history of the island,
an insight he applied throughout his travels.
While in South America, Darwin received Volume
2, which rejected the idea of organic evolution,
proposing "Centres of Creation" to explain
diversity and territory of species.
Darwin's ideas gradually moved beyond this,
but in geology he operated very much as Lyell's
disciple and sent home extensive evidence
and theorizing supporting Lyell's uniformitarianism,
including Darwin's ideas about the formation
of atolls.
== Criticism ==
Charles Lyell's Principles of Geology was
met with a lot of criticism when it was first
published.
The main argument against Lyell is that he
took an a priori approach in his work.
This means that Charles Lyell was pulling
from a theoretical idea instead of pulling
from empirical evidence to explain what was
occurring in the geological world.
One opponent of Principles of Geology that
agreed with this point was Adam Sedgwick.
This opposition from Sedgwick comes from his
thinking that evidence is all that is needed
to support an idea, and that the evidence
of geologic events points to a catastrophic
event.
The criticism of Lyell and his work continued
into the 20th century.
These arguments agreed with the a priori argument,
but continued on to say that Lyell combined
the empirical evidence with the scientific
explanation of geology that was accepted at
the time.The a priori argument is not the
only argument that Lyell faced for his work.
In 1812, Baron Georges Cuvier argued against
uniformitarianism with the results of his
study of the Paris Basin.
Cuvier and his colleagues found long period
of consistent change with intermittent patterns
of sudden fossil disappearance in the geologic
record for the area, which is now known as
mass extinction.
Cuvier explained these sudden changes in the
geologic record with catastrophic forces.
Lyell responded to this argument, stating
that the geologic record was "grossly imperfect"
and that observations cannot be trusted if
they go against "the plan of Nature".In recent
years, geologists have begun to question the
laws of uniformitarianism Lyell laid out.
There is now clear evidence of catastrophic
change caused by volcanic eruptions, large
earthquakes, and asteroid impacts.
Moreover, there is evidence that certain cataclysmic
occurrences that left marks in the geological
and fossil records may correspond to the periodicity
of the solar system's 26-million-year cycle
of movement around the galactic core of the
Milky Way.
Even if catastrophes are rare, their magnitude
may affect geology more than has been appreciated
under Lyell's version of uniformitarianism.
== Bibliography ==
1st edition, London: John Murray.
Vol 1, Jan. 1830 - Vol 2, Jan. 1832 - Vol
3, May 1833
2nd edition, London: John Murray.
Vol 1, 1832 - Vol 2, Jan. 1833
3rd edition, 4 vols.
London: John Murray.
May 1834
4th edition, 3 vols.
London: John Murray, 1835.
Vol 1 - Vol 2 - Vol 3
5th edition, 4 vols.
London: John Murray, 1837.
Vol 1 - Vol 2 - Vol 3 - Vol 4
6th edition, 3 vols.
June 1840
7th edition, 1 vol.
Feb. 1847
8th edition, 1 vol.
May 1850
9th edition, 1 vol. 1853
10th edition, 2 vols.
1866–68
11th edition, 2 vols.
1872
12th edition, 2 vols.
1875.
Vol 1 - Vol 2 (published posthumously
