The more I read about physics the more cases I find of discoveries being made at the same time by completely different people independently. The most logical explanation for these coincidences must be that people all have access to roughly the same body of information that is circulated among the science community. This allows people to put the pieces together and come up with things at the same time. So how many simultaneous discoveries can we list? 'Calculus' - Newton and Leibniz 'Klein - Gordon equation' – A few people at the same time.