In may fields of sciences, Perception is the process of attaining awareness or understanding of sensory information.
In my own personal opinion " Doubt is the key to knowledge", is very true. The reason being if you believed that everything is perfect as it is, and not doubting something or trying to get the right answer instead of dumbing down and agreeing to everything. With doubt you can get ideas to test things that you doubt about.
A great cultural example of this is when you have doubt about a different language like, french not knowing the language can mess some one up while on a trip to France or Canada, but once you ask or try to learn there is no more doubt about how to say hi (bonjour).
A great example from school is when you are learning something new in class, you might not understand it right away or you have a question about something (doubt) you ask the teacher and they explain therefore gaining knowledge of something new.
A great example from my personal life is when I have doubts about things that i might not fully understand or that I do not agree with, therefore I go out and try to find better answers and even though some times you might find that it was the same to start with, or it could be better and find a answer that you think is correct you always come out winning and with more knowledge even if it is correct or incorrect.