This may be elaborated with an example. Allah the Exalted has put in place three ruling forces within human beings. The first of them is the brain, the second is the heart, and thirdly, the tongue. The brain is supported by the intellect and makes use of argumentation. The task of the brain is to remain forever engaged in formulating and constructing ideas, and to reflect upon new arguments and proofs. The service entrusted to the brain is to compile data and then go on generating results.
The heart is the king of man’s entire being. The heart does not operate with the use of argumentation because it holds a connection with the King of all kings, and therefore receives knowledge either by way of manifest revelation, or by means of hidden revelation. It could also be said that the brain is a vizier and since the task of a vizier is to devise plans, therefore, the brain remains engaged in formulating proposals, reflecting on the necessary means, weighing arguments and producing results. In this, the heart has no part. For God Almighty has vested the heart with the faculty of sense. For example, an ant will find its way at once to a location where there is something sweet, although it is moved by no argument which proves that there is something sweet to be found in that location. On the contrary, God Almighty has granted the ant an instinct, which guides it to the relevant location. Likewise, the heart is similar to an ant, because like an ant, it too possesses the same faculty of sense which guides it. The heart does not require argumentation and proofs, nor does it have a need to analyse facts in order to extract results. Notwithstanding that fact, the brain does, nonetheless, provide the heart with these means and resources anyway.