One of the best outlines of secularization is given by John E. Smith in the epilogue to his book Experience and God. Here is his answer to what secularization means.
The answer can be given in its most concise form by means of five outstanding traits that not only mark life in the most highly developed nations of the West, but which now fire the imagination and spark the wills of countless millions in those lands we have come to describe as underdeveloped. These traits are autonomy, expressed individually as freedom and ethnically as national independence or the right of self-determination; technology or industrialization which means science transformed into human power over the environment and even man himself; voluntarism, with its closely associated individualism acting as the drive to control recalcitrant forces both in the inner depths of man and the temporal stretches of human history; temporalism, or a sense of urgency expressing itself with sharp focus on present existence and the immediate, and a corresponding lack of concern for the abiding, the time-spanning, and the long-range goal.These five traits structure and determine individual spirits as well as the spirits of nations and peoples, he says. They can be misused and indeed are often found in degenerate forms, as in the exploitation of the earth without regard for the autonomy of the earth, and the capitalist greed that drives technology without regard to its consequences to the earth and its inhabitants. But these traits of our secularized society are not, in themselves, the enemy of religion or any concept of God. They have, indeed, brought great good to the world, including for religion. We have a public space to talk about our various religions with respect now, for example. And, as Smith points out, it is the Western religious tradition that spawned secularization.
The fifth trait, which is closely connected with the preceding, is one for which it is difficult to find an adequate term; the basic feature is a concern for art, for the senses, for free self-expression, coupled with a feeling of relief wherever it is possible to break out of conventional patterns. This trait may be called “aestheticism” if the term is not understood in a basically derogatory sense, and If it is taken to include the two elements that must always be comprehended in art, namely, an appeal to significant sensible form and an expression of “free play” indicating that the system in which we live has relaxed its demands upon us. (pp. 181-82)
The question is, given that this is the secularized society we live in, what is the response of religion to that world? We may judge secularization’s abuses and deformations, but we cannot reject it out of hand and go back to a pre-secularized existence. Also, we have to ask what secularization has to teach religion about religion’s abuses and deformation? What does it have to tell us about religious traditions that use authoritarian tactics, running roughshod over the autonomy and free expression of its adherents? What does it have to tell us about religious traditions that force outmoded concepts and images of God on people who no longer even understand well what they mean? Or insist on a notion of God and humankind as the image of God that leads to the exploitation of the earth?
Today, if we are going to avoid social and natural disaster, religion has to be in conversation with the world we live in; it can’t stick its head in the sand and pretend we’re still living in the first or seventh or sixteenth or eighteenth or whatever century has been identified as the “pure” age for that religion’s expression. This is the world we live in, a secularized existence. How do we respond to that?