Immuneal Kant has proved the above statement as below :
If there is no role of the mind, how could the same experience leave one man mediocre,and in a more active and tireless soul(i.e.brain) be raised to the light of wisdom and the beautiful logic of truth?
Now, how a human mind learn?
A storm of stimuli beats upon the nerve-endings which help us to experience the external world through our sense organs.But not all the stimuli/calls/messages are accepted. The mind SELECTS only those that can be moulded into the perception suited to the present purpose of the person (or that brings life threatening fear.) Let the purpose be addition,and the stimulus "two and three" brings the response "five" ; let the purpose be multiplication, and the same stimulus brings the response "six". What a person learns form his experience is decided by the purpose of the person's mind.
This agent called mind arranges sensations into perceptions by allocating it the sense of space and the sense of time. Just as a human mind perceive a thing by combing the sensations about the thing with the sense of time and space; the mind conceptualizes the perception by categorizing them into causes,unity, relation, necessity,etc.
This journey of sensation to perception to concept becomes knowledge.
So,said Kant, absolute knowledge is impossible, if all knowledge comes from sensation, from an independent external world which owes us no promise of regularity of behavior.
But, what if the knowledge is independent of sense experience ? Can it then be the absolute truth? The wisdom?
Indian Philosophy answers the last question : "yes."
Go and read it !