[P]opulation, when unchecked, goes on doubling itself every twenty-five years, or increases in a geometrical ratio. ... [T]he means of subsistence, under circumstances the most favorable to human industry, could not possibly be made to increase faster than in an arithmetical ratio.
Thomas MalthusThe prodigious waste of human life occasioned by this perpetual struggle for room and food, was more than supplied by the mighty power of population, acting, in some degree, unshackled, from the constant habit of emigration.
Thomas MalthusThe main peculiarity which distinguishes man from other animals is the means of his support - the power which he possesses of very greatly increasing these means.
Thomas Malthus