One important idea in Berkeley’s writings is the doctrine of signs. “Berkeley was convinced that in drawing us towards what he called “materialism”- the belief that objects have an existence, “natural or real,” apart from their being perceived by the understanding [PHK 4] - human thought had failed.” Through further understanding of signification we might understand this failure. Berkeley went on to point to this failure through the understanding of abstraction. The abstraction principle that forms signification is based on the drawing from limited or incomplete information. Thus the natural attitude which is the basis for materialism is rooted in ignorance. At best it forms a conventional outlook.