Acquiring Information from Books

People need a vast amount of knowledge in order to live in an advanced technological society. Most of this has to be obtained from others by believing what they say and what they have written. Androids and sophisticated AI systems would also have to be able to learn in this way. This obvious fact tends to be overlooked by AI researchers (such as Pollock and Brooks) involved in the design of androids. They concentrate almost exclusively on belief-formation by means of perception. However, before we can program the ability to learn from others into an android we need to have a better understanding of human belief-acquisition. Elsewhere I have proposed a two-stage model of belief-acquisition. In the first stage we do acquire beliefs by means of our senses, but also from other people. In this latter case we make use of a defeasible rule, ‘Believe what you hear or read’. The second stage consists in the use of a sophisticated critical methodology in order to carefully assess a small number of our beliefs. In this paper I develop one part of this model in more detail. I look at the factors that cause us to override the defeasible rule to believe others in the situation when we are reading statements found in a book. This turns out to be far more complicated than may at first sight appear.