There was an air of inevitability that Christianity must change and adapt as new ideas, new discoveries, new facts, and new inventions shaped not only the external world but also the interior world, the landscape of the mind. What was true of the acceptance of changes outside the church became a point of challenge for the church in its mission to the world.
For this reason we have to distinguish between the particular circumstances that led to the phenomenom that we know as modernism or liberalism in theology, and the way in which culture, social change, naturalistic science and philosophy were brought into conversation with special revelation in Scripture. The former were part of the challenge to confessional faith during the nineteenth and twentieth centuries.
Some of those influences are weakened today, but they are yet to occupy spaces in the local cemetery for us visit. Yet we do recognise their limitations, and to a degree their influence has waned considerably. But liberalism was more than the product of a particular period. In a sense, and without wishing to be anachronistic, liberalism is also a mindset. It is a way of configuring culture and revelation so that the latter conforms to the ideas and dictates of the former. This means that the content of faith is consciously adapted, under the pressure of the culture it is seeking to reach, to the reigning thought forms and acceptable standards of the day.
The kind of liberalism that once dominated the church scene may well be in its final death throes. But the process of adaptation and accommodation to the culture continues, a process that inevitably reconfigures the content of Christian faith. It is this realisation that ought to make us pause as we assess the significance of postmodernism.
R. C. Sproul has a helpful brief summary of the effects of liberalism:
Nineteenth century liberal theology sought to reduce Christianity to a naturalized religion, stripped of everything supernatural. The Christian message was reduced to matters of ethics and values; the gospel was recast as a humanitarianism that attempts to alleviate pain and suffering in this world. Everything supernatural in Scripture was denied, including the deity of Christ. His substitutionary atonement, resurrection, and ascension were all rejected. Modern theology took hold of churches and educational institutions.
The second half of the twentieth century saw mainline churches in America lose members at the rate of a hundred thousand per year. In the 1970s the five largest seminaries in America were liberal. Today the five largest seminaries are conservative. People have left the liberal churches in droves because there is little substance in liberalism. Yet this liberalism has influenced evangelical churches, and evangelicalism has been seriously diluted during the last quarter century. This should motivate us to take steps to protect the church.R. C. Sproul, Truths We Confess Vol. 1, p. 171-2