One rarely sees scientific ideas spread by conquest,

The spread of scientific ideas from Europe was almost entirely by conquest.

or by the kind of social pressure brought to bear by religions.

Try being openly creationist at a major university, you'll quickly discover the kind of social pressure science can bring to bear.

Nobody gets told by their mother to believe Newton's Laws every week at college in the way they might be told to go to Mass.

Although they might get told to go to the doctor and not the New Age healer.