We each have a vast collection of proposition that we currently accept. These accepted propositions do not remain separate, they cohere together. This coherent collection of currently accepted proposition has been described as a web of beliefs.
Coherency provides a useful method of evaluation. Any newly encountered proposition gets compared to the collection. The acceptability of that proposition depends on its ability to cohere with our currently accepted propositions. Any proposition that lacks coherence with the collection easily gains rejection while any proposition that does have coherence easily gains acceptance.
While each of us has an individual collection of currently accepted propositions there are also other collections too. Any group has its own collection of currently accepted propositions. The evaluation of coherence can take place at each different level of grouping.
Similarity between our currently accepted propositions is what makes alliances possible. Alliances can be made between individual or between composite groups. These alliances can vary in their degree of strength. An alliance can be as simple as two individuals conversing or as complex as a political coalition. Communication depends on some degree of similarity in beliefs. Those who don’t share any currently accepted propositions cannot communicate.
Any collection of currently accepted propositions is dynamic. What was accepted by a man yesterday may not be accepted today. More significantly, what was accepted by most people 100 years go may not be accepted now and what is accepted now may not be accepted in 100 years.
The collection of currently accepted propositions is historic. We can research and discover the origin of each belief in the history of beliefs. No belief is non-historical. People can attempt to give perpetuation to a belief, but each belief still has a historic origin.