It is instructive to reflect on the past research of an entirely new material such as hydrogenated amorphous silicon in order to analyze which impediments lay in the way of reaching our present understanding. What in retrospect appears to be clear and important evidence was often not recognized as such and, therefore, not incorporated into a coherent picture for a surprisingly long time. One reason for the inability to see and understand is one's mode of thinking, which is conditioned by training and prior experience. Other impediments to progress are some persuasive, but erroneous, views of respected members of the scientific community. A third factor that tends to slow progress is a false sense of competition which, for example, prevents research laboratories from a fruitful exchange of materials and samples. It appears that human faults run neck to neck with nature's intricacies in slowing the pace of our understanding.