OverviewBelief, or the act of believing, can mean any of several slightly different things. The overall definition could be phrased as:
- the knowledge or understanding of a piece of information as truth
This comes in two somewhat different varieties, however:
- an acceptance that a piece of information corresponds to observable reality (to a sufficient degree that acting upon it is reasonable)
- "I believe that it will rain today, so we should probably bring umbrellas."
- "I believe that I can sit on this chair."
- This is also known as provisional or conditional belief, i.e. belief based on certain conditions. Changing the conditions can result in a change in the belief.
- the result of a decision to admit a piece of information as true regardless of observable reality (i.e. faith in an item of doctrine or dogma)
- "I believe that Jesus was born of a virgin, despite the fact that this is biologically impossible."
- "I believe that God will save us if we pray hard enough."
- This is is also known as unconditional belief. (Caveat: such belief is sometimes based on conditions which cannot practically change and have no logical connection to the belief. e.g. "I believe the world is flat because the Bible says it is." The condition -- i.e. what the Bible says about the matter -- cannot practically be changed, and photographs of a round world would be dismissed as a trick because the believer believes that the "truth" of the Bible trumps any external evidence. While technically "conditional", the actual conditions are immutable and -- more to the point -- have no logical connection with the truth, i.e. external reality.)
The reason for these two rather different usages may be due to subtly different usages of the word truth:
- that which accurately reflects reality
- This definition leads naturally to the "corresponds to observable reality" definition of belief.
- that which is agreed upon by all [in a given group]
- While this definition can lead to the "corresponds to" definition of belief if one is surrounded by people who agree that this is the proper definition, by the same token it can also lead to the "regardless of" definition.
 How to Distinguish
If a belief fails any of the following tests, then that belief is unconditional (i.e. faith) rather than conditional:
- (a) it is consistent with (or at least does not contradict) any evidence of which I am aware
- (b) the source of this information has previously been reliably proven correct on matters of this nature
- (c) There is further evidence which I can check for inconsistency if I so choose, at least in theory (i.e. the information is falsifiable)
 Indirect Evidence
Conditional belief does not have to be based on direct observation. While a belief based on indirect evidence may superficially seem like "faith", it is still conditional because it is possible to change the belief by demonstrating contradictory evidence.
Most belief in the findings of science is based on indirect evidence, as the body of knowledge represented by science is now far too large for any one person to understand completely; even the most knowledgeable scientists must accept large parts of it without direct evidence.
- "I do not understand subatomic theory, but I believe that the sun is powered by thermonuclear fusion."
- "I do not have a list of all the evidence easily at hand, but I believe the theory of evolution by natural selection is by far the best explanation for the origins of all known species including humans."
This fact is often used as the basis of a claim that belief in science is "taking science on faith", and that science is therefore just another religion. The difference, of course, is that religion does not satisfy criteria (b) or (c), and many religious claims fail criterion (a) as well.
RationalWikino information as of 2009-07-30
- LessWrong Wiki
Conservapediaredirects to faith as of 2009-07-30: apparently cp does not acknowledge the idea of believing things because they can be observed
 to file
- 2007-08-02 Belief as attire