Transcript: Scientific reasoning is an important part of how science works. You may have your own beliefs or your own faith, and they are your own. They’re unchallengeable. But if you make an assertion in a scientific way, you have to be able to back up that assertion. So when scientists argue about theories and models and data they are using a formal way of arguing about things that can lead to advances in knowledge. A scientist can only make an assertion if it’s backed up by evidence. They can only make an assertion if some other scientist could go out and verify the assertion. That’s the way that science proceeds. Why then do scientists argue so much? Often because there are multiple theories or models to explain a given set of data. Equally data itself is never perfect, is often limited, and sometimes has errors attached. These uncertainties allow scientists to have room for doubt and lead to the fact that not all scientists agree on every issue.