One of the interesting things about truth and orthodoxy, is that all the philosophy and theology connected to Revelation and Tradition hang together.
For example, if one believes that the priest is the alter Christus, then one believes that Christ is truly present in the bread and wine, which becomes the Body and Blood of Christ through the priest. And, if one believes in the Real Presence, one believes that the priest is the alter Christus.
Another example, if one believes that one of, if not the main purpose of marriage, is child bearing and child rearing, one would not contracept.
Yet, one more example, if one believes in sin and hell, one would see the need for Confession and absolution from the priest. If one believes in the efficacious nature of the sacraments, one believes in punishment and purgation.
And so on.
Truths come in logical, easily grasped, yet profound statements, upheld by the Catholic Church for over two millennium. The rationality of belief is connected, therefore, to morals, to worship, the Liturgy, and so on.
How we think is how we live our lives and how we live our lives is based on what we believe.
One cannot accept a little bit of truth, a little bit of orthodoxy and throw away the rest and be Catholic.
Of course, for years, we have used the term "cafeteria Catholics" to describe those who pick and choose which beliefs they want to uphold and which they want to deny.
Cafeteria Catholics are apostates, those who have decided to not believe in all the teachings of the Church and who have decided not to obey, even when they do not understand fully a truth.
At worst, cafeteria Catholics are heretics, picking up a false belief, not merely rejecting, but accepting something else which is man-made error.
We call this a Protestant stance or mind-set. For example, the Protestants threw out apostolic succession and the connected belief in the True Presence of Christ in the Eucharist.
To believe Holy Communion is a mere memorial constitutes believing in a condemned heresy.
One cannot accept a little bit of this and a little bit of that and be saved.
Because the Truth is a Person, and that Person clearly told us this.