From The American Conservative: Evolution, Individualism, and the End of the Family. It’s a long article and this quote comes near the end, but I highly recommend the entire piece to you.
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To a large extent unintentionally, but surely and dramatically, the three great philosophical movements of the nineteenth century—individualism, statism, and evolutionary progressivism—drove familism to the farthest extreme of atomism. In most states, the industrial revolution loosened the family from parental control. Its first result was a rapid increase in the birthrate of these industrial countries, followed by a rapid decline. By 1870–80, the birth rates had begun to decline in almost all European countries. Except in the peasant-agrarian countries of Eastern Europe and Southern Italy, they were below reproductive levels by 1930.
Legal backstays of the family—some degree of manus, potestas, coverture, and mutuality—were destroyed on a large scale, more so in some countries and periods than in others. The individual arose and became the subject and the dependent of the state. Theories of the family as but a nominal group, a private contract to be broken at will, gained ascendancy. The minds of the people were being filled constantly with the idea that “happiness,” as defined by individual egotism, was the goal of life. Marriage and family must justify themselves according to this concept of “happiness” or be abandoned. Happiness is a very subjective term, being defined each moment, each day, and in each age by different psychological considerations. Consequently, the family had no understandable objective for its guidance.
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