Throughout the Middle Ages the Scriptures and the Patristic writings were sacrosanct and could not be questioned, but some Schoolmen were prepared to look critically at classical writings. One of these was Roger Bacon. As we saw in the previous chapter both Bacon and Grosseteste had based their views, at least in part, on direct observation and both had made discoveries that supplemented Aristotelian physics. Bacon argued that classical writings should not be treated as setting absolute boundaries on what could be known. It was not that Bacon had no respect for Aristotle, or for other secular authorities, indeed he appealed to these authorities to support his contention that no one should rely solely on authority. Nevertheless he advocated a critical approach to established opinion and to established writings. He listed four kinds of impediments to the search for knowledge which are remarkably similar to those discussed by his equally famous namesake Francis Bacon, over three hundred years earlier; there is no evidence that the two were related. These impediments were:
1 Reliance on frail authority, though he stressed that he was not referring to Holy Writ.