It is said that tadabbur (contemplation) is necessary for marefat (God-realization). 
I believe it is also important to have triggers for marefat. 
If you are not mentally prepared such that your mind gets triggered, then even if you study and do tadabbur, your level of marefat will not increase. 
This concept is present in the Quran. 
The word 'trigger' was developed after the invention of the gun. Earlier there were no guns. 
The word used for this concept in the Quran is tawassum. 
Tawassum means triggering of the mind on observing something, which then leads to a discovery. 
This concept was present among the Companions of the Prophet. 
The Quran says: Copy Arabic text

"There are certainly signs in that for those who can learn a lesson." (15:75)
In today's language I will express this as 'those whose minds can be triggered'.
Otherwise, you will not be able to take a big lesson from God's signs. 
I will give an example. 
The Prophet once observed that some birds were innocently going about their work. 
Birds are very innocent creatures. This shows that their hearts have hatred for none. 
When the Prophet saw these birds, he said this is how the people of Paradise would be. 
Copy Arabic text (Sahih Muslim 284)
That is, they will be people who have peace, love and well-wishing in their hearts.
They will have no negative thought for anyone. 
The Prophet saw birds, his mind was triggered, and he saw a picture of Paradise. 
If you do not have the ability of tawassum, you will never attain higher levels of intellectual development. 
You will not be able to advance toward marefat.  
Observation, study and contemplation are very important. But for greater God-realization, tawassum, or triggering of the mind, is very essential.