The truth would emerge by itself from the documents if you looked hard enough. Thus historical knowledge accumulated and we knew more and more about the past - not for some future project or present ideology, but for its own sake, which was the only proper reason for undertaking the study in the first place. Elton's views have had a wider currency than Carr's. But they too now seem dated. His views on the Tudor period were widely criticised, and it is clear that he did shape his arguments in conformity to his own strongly held political beliefs.
Few historians believe that interpretations spring unaided from the sources.
Most would accept that they do not just listen to the evidence, they engage in a dialogue with it, actively interrogating it and bringing to bear on it theories and ideas formulated in the present. Not only is it impossible to leave such ideas behind when you go through the archive door, it is also undesirable. At the same time, however, most historians would accept that their dialogue with the sources is a two-way affair. If your documents come up with things that upset your beliefs, then you must be prepared for a rethink. Carr believed this just as much as Elton did.