Paradigm shifts in Mathematics? Do they exist?

I'm trying to think about a paradigm shift in math, but cannot seem to find any. There are obviously shifts in science, arts etc, but math doesn't seem to change. Sure there are conjectures and such that are refuted every now and then, but there is never really a reversal of thinking about math. If you have any examples of paradigm shifts in mathematics, that would be really helpful. Also if you could post sources. Thank you.