Why do we doubt?

[Edwardo Piet]

We doubt because we're rational.

I'm more interested in why most people don't doubt and believe in a god.

Here's why I think it is:

http://www.thedailybeast.com/articles/20...rains.html

Insights from neuroscience suggest that the brain tends to automatically accept rather than reject beliefs, oftentimes independent of how logical they might be.
[...]
elieved in a number of statements. Sentences ranged from the very simple and fact-based (California is larger than Rhode Island), to the abstract and highly subjective (God probably does not exist). The data revealed activation of distinct but sometimes overlapping brain areas during belief versus disbelief conditions.
Additionally, the scans clearly showed something that was more straightforward. Brain activation, overall, was much greater and persisted longer during states of disbelief. This is important because neuroscience has long shown that greater brain activity requires more mental resources, of which there is a limited supply. A cognitive process that demands little mental resources, such as believing, is less work for the brain and therefore favored. This concept was summed up nicely in a 2015 NewScientist cover story on the science of beliefs, which stated, “Harris’ results were widely interpreted as further confirmation that the default state of the human brain is to accept. Belief comes easily; doubt takes effort.”

If I remember correctly the philosopher Spinoza also reckonened that belief was the default state.

It also explains why people often jump to conclusions and make assumptions. It's easier because it's useful for people to jump to conclusions like that.

So to doubt something we need a reason. I.E. we want to be rational, we care about the truth, etc. Otherwise the default state is to jump to conclusions.

Thankfully some of us are naturally more rational than the average person.