History and science are complementary, which means they are in some way opposite but they fit together to make a whole. It also means they cannot be merged into one another, but have a separate identity even as they work together.
History is about particulars. Science is about universals. They are similar in that they contain both particulars and universals, but their focus is different. The goal of history is to establish particulars. The goal of science is to establish universals.
Science is about what can or must happen. History is about what actually happened. The particulars of an experiment are the history of what actually happened. The universals of an experiment are the science of what could or must have happened. The particulars of a series of events are the history of what actually happened. The universals of a series of events are the science of what could or must have happened.
History has the final say on what actually happened because its goal is to establish the particulars of what actually happened. Science has the final say on what could or must have happened because its goal is to establish what could or must have happened. Science cannot annul history. Scientists cannot say, for example, that the French Revolution never happened because their theories don’t allow it. Historians cannot say, for example, that the Second Law of Thermodynamics is false because their histories don’t include it.
What if there’s a conflict between history and science? What if history determines that something actually happened that science says is not possible? As far as the particulars of what actually happened, history has the lead and so the position of history is final. As far as the universals of what actually happened, science has the lead and so the position of science is final.
This would be a paradox but not a contradiction. Science and history would not be talking about the same things in the same the way. A particular that actually happened but does not fit the universals of science would be an example of the incompleteness of science. A universal that was more narrow than the particulars of history would be an example of the inconsistency of history.
Science is incomplete, not only in the sense that the limits of a theory are not known until the theory is superseded, but also in the sense that science must be consistent and so reject anything that doesn’t fit its universals. History is inconsistent, not only in the sense that the sources of history conflict with one another, but also in the sense that history must incorporate particular changes that actually happened.