There are two kinds of argument for theism. Traditional, epistemic arguments hold that God exists; examples include arguments from cosmology, design, ontology, and experience. Modern, pragmatic arguments hold that, regardless of whether God exists, believing in God is good for us, or is the right thing to do; examples include William James's will to believe and Blaise Pascal's wager.
Pascal -- French philosopher, scientist, mathematician and probability theorist (1623-1662) -- argues that if we don't know whether God exists then we should play it safe rather than risk being sorry. The argument comes in three versions (Hacking 1972), all of them employing decision theory.
For those who are unfamiliar with decision theory, the idea can be illustrated by considering a lottery. Suppose there are 100 tickets at $1 each and a jackpot of $1000. Is it rational to play? If you total the earnings and the expenses for all the tickets ($1000 - $100), then divide by the number of tickets, you find that on average each ticket nets $9. In comparison, not playing involves zero expense and zero payoff. Since $9 is preferable to $0, it is rational to play. Alternately, suppose there are 1000 tickets costing $2 each, a grand prize of $1000, and a consolation prize of $500. Then the total earnings and expenses ($1500 - $2000), divided by the number of tickets, yields a net loss of fifty cents for the average ticket. In this case, unless you have some reason to believe that a given ticket is not average, playing the game is irrational.
To put the matter more generally: a given action (say, buying a ticket) is associated with a set of possible outcomes (say, winning the grand prize, winning the consolation prize, or losing); each outcome has a certain value or "utility" (the utility of winning might be the value of the prize minus the cost of the ticket); the "expectation" for each outcome is equal to its utility multiplied by the probability of its happening; the expectation for a given action is the sum of the expectations for each possible associated outcome. The course of action having the maximum expectation is the rational one to follow.
Do you believe because it makes you feel better?
Do you believe because the alternative is overwhelmingly horrifying to you?
Do you believe because you feel that in so doing, you have everything to gain and nothing to lose?
I have read some sincere people on JWD that believe for the above reasons.
What about you?
Is fear or calculated pragmatism driving your belief?
Can an all-knowing benevolent deity be satisfied with worship/belief motivated by either?