Statements can be significant despite being “statements of the bleedin’ obvious”. The philosopher David Hume’s remark that "The rational man adjusts his beliefs to the evidence" falls exactly into this category. It is surely “bleedin’ obvious” that our views (and hence our policies) ought to be based on evidence, but Hume’s claim is important exactly because it is so often ignored in practice. In these Trumpish times of disinformation and fake news, people’s views seem more and more to be based on what they would like to be true rather than on any evidence that they are in fact true.