To Believe or Not to Believe that is the question
“Do not believe in anything simply because you have heard it.
Do not believe simply because it has been handed down for many generations.
Do not believe in anything simply because it is spoken and rumored by many.
Do not believe in anything simply because it is written in Holy Scriptures.
Do not believe in anything merely on the authority of teachers, elders or wise men.
Believe only after careful observation and analysis.
When you find that it agrees with reason and is conducive to the good and benefit of one and all, then accept it and live up to it.” —Salman Khan
Believe is one of many words used in our language that can easily mislead and misrepresent the user's intent. This can be attributed to its' denotative and subjective subtleties. It seems "believe" is the catch all verb of choice.
believe (verb) 1. to accept as true or as speaking truth. [synonyms: -be certain of -put one's faith in] 2. think; suppose. [synonyms: assume, maintain, presume] to believe in 1. have faith in the existence of. [synonyms: swear by; trust in; have faith in ] 2. feel sure of the worth of.
belief (noun) 1. firm opinion; acceptance "that is my belief" 2. religious conviction "he has no belief" 3. belief in: trust or confidence "belief in the justice system" 
How we use the word
There are two circumstances in which to use the word "believe"; the religious and the rational. By religious, I mean a fundamentalistic zealous attitude towards the belief. In the religious viewpoint, the act of believing is to accept as true or real without need of additional confirmation or proof. We often think this only applies to religious situations but it can apply to any domain. There is a problem with this attitude; it does not allow for change or growth. The person who uses this standpoint already accepts the belief as FACT.
The rational version of the verb "to believe" allows for change because its acceptance of truth is based on assumption and conjecture. This standpoint allows for mistakes and as humans, we have the capacity to learn from our mistakes. The following scenario is over simplified but it goes something like this:
What is the Earth's shape?
The religious believer—"I believe the earth is flat." I know this to be true and nothing you are going to say will change my mind because I am right.
The rational believer— "I believe the earth is flat." I presume this is so, because when I walk I appear to go in a straight line.
Note: With the rational outlook, the presumption can be tested and tried until it has mutated into fact or knowledge with evidence to support it.
— and the answer today?
The standard response is: “the earth is round”, but to be more precise, it is really an oblate spheroid.
For more information: an excellent detailed explanation of the implicit and explicit usage of belief can be found at the following link: The Internet of Encyclopedia of Philosophy.
How we believe
Humans are pattern seeking creatures. This skill, of being able to establish patterns and causal relationships, seems to be inherent in our nature and is attributed our survival instinct. Patterns are ascertained through experience. The problem is knowing which pattern is beneficial, harmful or useless. We learn what works and doesn't work through repetitive experiences.
For example: Early humans learned the pattern of the seasons and eventually developed agriculture.
Natures' patterns can be observed and learned but what of the abstract concepts like magic, religion and god. —How did we begin to (religiously) believe in what we couldn't see? Below are a few possible theories of the origins of spiritual belief:
* Humans are born with the inherent capacity to believe in mystical concepts
* Early man manifested the "abstract" for those situations where there were no patterns to establish reason; a kind of Proto-science if you will.
* Mysticism is a false paradigm that our ancestors accepted as truth and is now slowly de-evolving through the expansion of scientific knowledge.
* Earth was visited by an advanced culture in ancient times and early man developed the divine concept. —Not my most favored theory, I must admit.
Why we believe
Each person will have their own reason for believing or not believing in something; be it from the religious or rational viewpoint. When it comes to religious spiritual beliefs it could be for any number of reasons. In the following list, god is used generically to reflect all possibilities and is not gender or denomination specific:
* Believing in god answers the need to believe in something.
* An individual believes in god because they were taught to believe.
* God must exist because there exists a living universe.
* God gives life meaning and purpose; by helping define our sense of self.
* God provides control and guidance in life through fear of retribution. Depending on the belief this can be in the present, in the afterlife, reincarnation or karma.
* There has to be more to life than 'life and death'.
What we believe
I cannot answer for anyone else. ~For myself, I find patterns and rituals comforting and meaningful. I know that I need more than just rationalization to explain my world. For some it is science, for others it's religion but for me --the answer lies somewhere in between.
Something to think about
Given the assumptions:
(a) There appears to be a hierarchical order within nature.
(b) Awareness may or may not exist between levels.
Is there hierarchical level above man?
Would you call "it" god?
Is it something we, as humans, can define?
Does it care about the lower levels within the hierarchy?
Should it be revered?
Will science meet all the needs of humans beyond the realm of logic?