Kant- how is pure natural science possible?

Kant says, nature is the existence of things, so far as it is determined according to universal laws. He says that the nature of things in themselves are neither a priori nor a posteriori. He says that things with the nature or things with experience are a priori. Things such as physics, mathematics, and substance. Kant asks this, "how can we cognize a priori that things as objects of experience necessarily conform to law?" He answers, "...whenever an event is observed, it is always referred to some antecedent, which it follows according to a universal rule; or else, everything of which experience teaches that it happens must have a cause. This section really made me think about Hume's book and his section on miracles and how they are impossible to occur.