Quote from : Humanism: An Introduction Book

The widest cause of secularization may be the steady change of thinking so that there is the expectation that reason and a consideration of cause and effect will help with explanations. Supernatural power began to be removed from explanations of the process of life or society in the seventeenth century, and although there may be a nod towards astrology or the crossed finger today, superstition is not seriously used in decision making. ... Scientific thinking, which similarly developed in the seventeenth century, has been influential in bringing this change. We now see that tornadoes and earthquakes have rational explanations in terms of climatology and seismology rather than as divine punishments. Most people when deciding whether to take a new job, embark on a divorce, or simply plan a holiday will not seek divine guidance, but rather discuss with themselves or others the issues of cause and effect.