Having disposed of natural theology, Modernism then proposes immanentism to explain what religious experience is supposedly all about. Human beings, the Modernists argue, are invested with a “religious sense” which wells up out of the unconscious and creates in us a need for the divine. It is in response to this need that we positively respond to ideas about the reality and nature of God which, as it happens, are comfortably conformable to our feelings. What this comes down to, in practical terms, is that the “God” to which one gives one’s allegiance is but a fiction of one’s own devising, a pseudo-being having its source nowhere else but in the demands of deep-set emotions. Here Modernism can be said to be reflecting the thought of the nineteenth century atheistic philosopher Ludwig Feuerbach, who argued that what we call God is no more than the imagined product of human longings and wishes.
http://fssp.com/press/2011/04/immanentism-catholicism-and-religious-experience-by-d-q-mcinerny-ph-d/
I like this emphasis on people claiming they know God, but in reality, they have defined Him in their own terms.
Instead of dying to self and being open to the real God, people who only worship themselves, or what they think if the image of God in themselves, fall into deceit. As noted above, this deceit leads to an emotional sense of being, rather than a rational one. The god within is merely a reflection of egotism and sin. Part of the huge problem today of many people who are living a godless life, is that they honestly believe they are "religious" or "spiritual", when in reality, they are merely caught up in idolatry.
Sadly, some Catholics have fallen into this idea of immanentism, thus denying the need for the sacraments and, therefore, sanctifying grace.
To be continued...