The OED states: belief is the acceptance of something that exists, or is true without proof. The earliest word for belief is geleafa from Old English, which means to hold dear and trust. It was replaced by bileave in the late 12th century and finalized as believe in the 15th century. There are numerous words that are similar that describe belief, from gilōvo of Old Dutch, gelōve of Old Frisian, to gilōbo of Old Saxon. Throughout the course of its etymology, it shows a significant overlap with the word faith. Both through its evolution its meaning now has different focuses. While belief was the trust in God, or the acceptance of propositions, faith, was the loyalty to an individual based on the premises of a promise, or an obligation.
One definition of belief directly relates to the basis of how religion works. It defines belief as the trust in the existence of a higher power. When following the teachings of God through given duties, and religious texts, gives an individual a sense of purpose, and strength to carry on, especially during difficult times. But on the other hand, a blind sense of faith can result in conflict. The disagreement between different faiths has been the catalyst for many religious wars in human history.
Philosophical belief is virtually an individual’s opinion. With each individual comes a different set of traits, experiences, and emotions. These all factor into how we perceive or interpret what we read and experience. The beliefs of each of us are ultimately individualistic, because we all live in unique circumstances. Externalism is the thought that mental states like belief are related, and affected due to the surrounding environment. Lewis Wolpert, a well-known philosopher and biologist, suggests belief has a map like representation rather than a linguistic structure. He states that once an individual changes one belief, other beliefs are simultaneously effected.
In defining belief, we also have to explore the meaning of knowledge as the two are interrelated. According to the Gettier problem, which is a category of thought experiments, knowledge is a species of belief, known also as a justified true belief. In some senses, truth is often distorted by how we perceive or believe in something. But the general agreement of truth can be altered if the majority shares common beliefs
Belief can also just simply represent the action of trusting, or having confidence in someone, or something. It can also be the acceptance of truth from the mouth of a speaker. It is a willing sense of reliance, and dependence not based on scientific inquiry but based on the ability to trust and accept truth from the mouth of a speaker.
1) Oxford English Dictionary. "belief," http://www.oed.com/view/Entry/17368?redirectedFrom=belief#eid (added to OED in 1175)
2) Wikipedia. "Gettier problem," http://en.wikipedia.org/wiki/Gettier_problem (last altered on Nov. 11, 2012)
3) Lau, Joe. Deutsch, Max. "Externalism About Mental Content," http://plato.stanford.edu/entries/content-externalism/ (2010)
4) Harper, Douglas. "belief," http://www.etymonline.com/index.php?term=belief&allowed_in_frame=0