Imaan (belief with certainty) is to not contradict yourself.

Why is intuitive logic a valid tool of reasoning in matters of imaan?

Years ago this question made me doubt that one can be certain of the existence of 1 God. In fact reaching the conclusion of the necessity of 1 God required the assumption that our intuitive logic is necessarily true. Later I realized there was something inconsistent about this idea, however, I couldn't pinpoint it exactly and simply brushed over the idea that intuitive logic must be a valid tool as a "gut feeling". Today I am trying to express it in more clear and convincing words than just a "gut feeling". 

(Intuitive logic such as: 

"If something exists, its existence must have been chosen over its non-existence."

OR

"Sifat mevsufsuz olmaz. Attributes cannot exist without the one qualified by them. An attribute cannot be without the one it qualifies." (from Sozler, 33. Soz, 16. pencere; The Words, 33rd Word, 16th Window by Said Nursi)

etc)

http://plus.maths.org/content/mother-all-theories

""So [seeing supersymmetry] would be evidence for the power of pure reasoning, the power of the human mind."Last year results from the LHC at CERN made a splash, providing strong evidence for the notorious Higgs boson (you can read more on this on Plus). This counts as a triumph for the power of the human mind: it was purely theoretical considerations that led the physicist Peter Higgs to predict the particle's existence nearly 50 years ago. Now it has, to all intents in purposes, been found. "

Without intuitive logic, maths and sciences wouldn't exist or advance. Whether it is limited or faulty, just like our sensual perceptions of the universe, our logic too is a tool we have to rely on to reach any analyzing conclusions about theological/existential matters. For we cannot rely on something which we do not have (such as eyes, mind, etc) and cannot build (such as observatory measuring tools). If we were to deny this, we might also have to deny our perceived existence. 

"Observation by effect" rather than "direct observation" is a common tool in physics and provides the foundational approach of many imaan (belief with certainty) principles.

Such as: "we see some of the creation, some of the effects of God, but we do not see the Creator"
"We see the effects of the particles within the atoms but we cannot see the atoms nor the far smaller particles within them."
"We can see the effects of electricity, force and energy (such as light), however we can never see themselves." 

Similar logic can be extended to all human faculties including emotions. If we are to analyze our existence and to question the purpose of the universe of which we are a tiny part, we are bound- by necessity and lack of alternatives- to use the data and donnee at hand and -by the desire to be all-inclusive and complete- to use all we have at hand. 

Thus a statement such as:

"The rain is an act of mercy." 

cannot simply be dismissed on grounds that it's an emotive perception. In fact there is no objective approach that can value the philosophical significance of logic over emotions over imagination over sensual perception over perception through the use of tools. As far as the human is concerned, they are all equally valid tools that need to be used exhaustively in order to reach or confirm complete and consistent formulations.

In this way, as an example of Qur'anic reasoning, when we combine 

"The rain is an act of mercy and wisdom and power." an emotive conclusion also based on knowledge and observation (living beings are consisted mostly of water, force is needed to descend water from the sky to earth, etc),

with

"An attribute cannot be without the one it qualifies." an intuitive logical statement,

with 

"Objects such as the clouds or the water drops cannot be the source of mercy and wisdom and power" also an intuitive logical statement,

with 

"A city cannot have two mayors, a country cannot have two presidents, therefore the universe which is organized in unison and harmony cannot have two governors" an intuitive social and logical statement,

we reach the logical conclusion of:

"The rain is an act of the Merciful, Wise and Powerful One, One who is not an object of this universe and One who governs all of the universe."

In summary: Imaan (belief with certainty) is to not contradict yourself. There is no other way that we can test our conclusions.