We desire knowledge of what is true. We thus act in a way to remove or remedy our doubt. Science has made good use of doubt. Doubt about this or that model or theory lead a scientist to develop a better model or theory. Doubt acts as the gadfly of progress.
Natural science is the process of doubt and resolution.
This process leads to the net gain of bits of information. In religion doubt is a different matter. This naive view of the relationship between doubt and faith has done much harm to religion. Any religion which prohibits doubts abandons any hope of growth or development. A religion without doubt is fixed and unchanging.