freedom of thought
At the basis of human personality is a certain power of the intellect to discriminate between true and false.
To this extent the intellect is "free," as contrasted with a purely mechanized reaction disregarding the truth or falsity of a proposition.
"Freedom of thought" in this sense "is necessary for freedom of will as opposed to determinism.
However, one is not free to think anything at all, as, that two and two make five.
In so far as the intellect recognizes a statement as true, it is not free to think it false.
As long as a man's thinking remains purely internal, it is, of course, beyond the control of the State, but it may indirectly coine under the control of the Church.
Thus one who recognizes the infallibility of the Church is not free to think that on a particular point, as the Virgin Birth, she has erred.
New Catholic Dictionary