Sometimes we may be tempted to suppose we automatically have Christian Science because we are church members or we've been studying Christian Science for a while. Yet the truth is we have Christian Science only to the extent that we've actively replaced old thought with new. And the process, to put it mildly, isn't completed overnight!
The old thought is mortal mind's false impression of things. We could say, in a way, that mortal mind has its own "religious" view, just as it has its own view of everything else, from law to substance to health.
What is mortal mind's "religious" sense? It often includes an impression of trying to be good and never quite succeeding. There may be the feeling of being essentially material but trying desperately to become more spiritual. And there are many other elements to this mortal mind "faith"—such as the superstition that too much good is dangerous and vulnerable to reversal. So, unless we are consciously working to replace these opinions with Christianly scientific facts, and we work at it consistently, we are apt to find ourselves lost and wandering in old religious patterns.