1. There has long been a superstition among mariners that porpoises will save drowning men by pushing them to the surface.
    长久以来, 海员们有一种迷信, 那就是海豚会把很快要淹死的人推到水面使之获救,

2. There has long been a superstition among mariners
    长期以来，海员中流传着一种迷信的说法，

3. He holds that ignorance leads to superstition.
    他认为无知会导致迷信。

4. It was necessary first to arrive at that degree of sophistication where we no longer set our own belief against our neighbour´s superstition.
    我们首先需要达到这样一种成熟的程度：不用自己的信仰去反对我们邻居的迷信。