The Industrial Revolution (^) ‹ 139
• There was further change in the class structure, as industrialization created both a class of
newly wealthy industrialists and a precariously situated lower-middle class of managers
and clerks.
• Close working and living conditions produced a sense of class consciousness among the
working class.
• New advances in communication, such as the telegraph, telephone, and radio, created
more integrated societies and economies, eventually paving the way for a global eco-
nomic network.
Science in an Industrial Age
Advances in gas theory and a spirit of scientific realism dominated the physical sciences
in the nineteenth century. Physicists in this period concentrated on providing a scientific
understanding of the processes that drove the engines of the Industrial Revolution. In the
middle of the nineteenth century, the German physicist Rudolf Clausius and the Scottish
physicist James Maxwell developed a kinetic theory of gases. Their theory envisioned gas
pressure and temperature as resulting from a certain volume of molecules in motion. Such
an approach allowed them to analyze, and therefore to measure and predict, pressure and
temperature statistically. Later in the century, physicists such as Robert Mayer, Hermann
von Helmoltz, and William Thompson pursued this kind of statistical analysis to articulate
the laws of thermodynamics.
The success of “matter-in-motion” models in physics created a wider philosophical
movement that argued that all natural phenomena could and should be understood as a
result of matter in motion. The movement, known as materialism, was first articulated by a
trinity of German natural philosophers: Karl Vogt, Jakob Moleschott, and Ludwig Büchner.
By the end of the nineteenth century, materialism had become the foundational assumption
of the scientific view of the world.
The natural sciences of the nineteenth century were dominated by Charles Darwin’s
theory of evolution by natural selection. As a young man, Darwin had sailed around the
globe as a naturalist for the H. M. S. Beagle. During the Beagle’s five-year voyage, commenc-
ing December 27, 1831, and ending on October 2, 1836, Darwin collected specimens for
shipment home to England and made observations on the flora and fauna of the many
continents he explored. Twenty-three years later, he published a book titled On the Origin
of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle
for Life. In Origin of Species, Darwin offered an answer to the two questions at the heart of
nineteenth-century natural science: why was there so much diversity among living organ-
isms, and why did organisms seem to “fit” into the environments in which they lived?
Darwin’s answer, unlike earlier answers that referred to God’s will and a process of creation,
was materialist. He argued that both the wide range of diversity and the environmental
“fit” of living organisms to their environment were due to a process he termed “natural
selection.” The fact that many more organisms were born than could survive led, Darwin
explained, to a constant “struggle for existence” between individual living organisms. Only
those individuals who survived the struggle passed their physical characteristics onto their
offspring. Over millions of years, that simple process had caused populations of organisms
to evolve in ways that produced both the amazing diversity and the environmental “fit.”
Origin of Species went through six editions, and Darwin’s theory became the central organ-
izing principle of the science of biology, which developed in the late nineteenth and early
twentieth centuries. In 1871, Darwin published The Descent of Man, which explained Darwin’s
views on how human beings had come into existence through the process of natural selection.17_Bartolini_Ch17_133-142.indd 139 27/04/18 1:55 PM