In short, I do claim that “all science is Christian science”.
So, can pagans do science? No, or yes only to the extent that they abandon pagan thinking and adopt Christian thinking, as the ancient Latin and Greek worlds did. What about heretics? Certainly they can, to the extent that they retain Christian thinking. A heretic is by definition a Christian of a sort, although the particular bent of a particular heresy might preclude it.
What about a post-Christian society, such as ours, or a never-Christian society such as Japan? It remains to be seen, I think, but the signs are not good so far.