Fideism (pronounced “fee-day-ism”) is a Christian heresy that can best be explained as blind obedience to any external authority, be it educational, religious, governmental or even medical. Basically, whenever we make a decision because someone else told us we should, we have succumbed to fideism. We have handed over our own personal authority and choice to someone or something outside of ourselves.
Choices we make, must be made by learning as much as we can from others, but then ultimately discerning what God wants for us in the deepest interior of our hearts. Put another way, we must form our own conscience well, listen carefully (to those outside, but also to our interior) and then make our own decisions.
But fideism happens in other ways too. We often hear people say something like “I’ll be happy when . . .” fill in the dots; I get married, my spouse stops drinking, get that job, finish school, buy a house, have children, etc. Again, this is also fideism. When we do this we are handing over our own choice for happiness to an external person, situation or thing. Our choice for happiness is a decision that we make for ourselves. It is not dependent on exterior events, persons or situations. Our interior state is not dependent on exterior things.
Actually, you already know this, because we all know people who have been happy in spite of living in terrible situations. Think of Dietrich Boenhoffer or Nelson Mandella. Etty Hillesum is another example. Read her book An Interrupted Life for an uplifting look at a young woman who chooses for love and happiness in the midst of tragic circumstances.
Ultimately, we need to inform ourselves, face reality as it really is (and this is not always easy), listen to our own hearts, then make our own decisions about what we will or will not allow in our lives. This can be a long and gut-wrenching process to be sure.