As we know, man's knowledge, compared with what is unknown to him, is like a drop of water in the sea. If man wants to capture this drop of knowledge, he has to select the proper method of approach so as not to get drowned in the immense sea of what is unknown.

In his letter, Imam ‘Ali (as) provides us with three such approaches:

1. Inspiration

As Allah is the Creator of existence, and is aware of every detail, definitely His book of religion is based on the facts of His book of creation. No deceit or lies appear there. Thus, a resort to Allah's Book and to the Prophet's tradition, which is identical with divine inspiration, can help us find our right path and block our deviation. For this reason, Imam (as) has emphasized: “What I would like the most for you to take from my will is Allah-wariness, restricting yourself to what Allah has imposed on you”.

As we know, one of man's most important ways for the progress of knowledge and culture and man's civilization, has been following the guides offered by the Prophets and the Imams (as). We have dealt with this in the book called "The History of the Islamic culture and civilization."

2. The Ways Of The Pious Ancestors

It is a fact that the older generations of a community, especially if they have had the guidance of Divine Prophets, through experience and inspiration, have amassed huge reservoirs of knowledge, which could be a valuable treasure for the next generations. Thus, reliance of this worthy treasure could help us attain the right knowledge. That is why in this letter, Imam ‘Ali (as) orders his son to follow what his forefathers have done.

Since we know that the Prophet and the Imams are descended from sacred origins and are not afflicted with impurities of unbelief and have always followed the right religion, therefore, their ways are felicitous and their knowledge is based on rights and facts.

Do his ‘forefathers’ mean the Prophet (S), Abu Talib, Abd al-Muttalib, Hashim…? And do the ‘righteous among the people of your household’ refer to Hamza, Ja’far, Abbas, etc?
Of course, this adherence to the practice of the pious ancestors does not clash with blind imitation, which we will study later. This kind of adherence is the reference of an ignorant person to a scholar. This is because these pious scholars are righteous people and will not misguide us. Secondly, as it is in the text of the letter, they contemplate their daily affairs and do not get into matters they know nothing about.

3. Logic and Reasoning

The third way to get to truth and knowledge is through reasoning and logic. The Holy Qur’an says regarding this:

"And follow not that of which you have not the knowledge; surely the hearing and the sight and the heart, all of these, shall be questioned about that" [Qur’an 17:36]

Contrary to other religions which contend that in the matters of belief and practice, worship itself is enough, Islam is of the opinion that each idea or practice is acceptable only if it is based on logic.

"And they say: None shall enter the garden (of paradise) except he who is a Jew or a Christian. These are their vain desires. Say: Bring your proof if you are truthful." [Qur’an 2:111]

On the basis of this, Imam ‘Ali (as) mentions: if you do not wish to use the first and second approach, and if you want to use the third way, you should use good understanding and reasoning, not baseless assumptions.

If your soul refuses to accept that without ascertaining it (for yourself) as they ascertained it, then let your search for that be with understanding and study,

The conditions for the use of this third method include the following:

a) Asking Allah for assistance.

b) The intention should be the clarification of the truth, and not quarrel or the defeat of the foe.

c) Drawing away the prejudice of defending one specific religion, the intention being only the clarification of the truth, or else it would be of the other type, which leads to misleading.

d( Driving away those factors which make man doubtful, such as: megalomania, desire for fame, too much interest in one’s possessions.

e) Having a pure heart, away from any kind of doubt and depression (such as hunger, too much eating, aggressive lust, anger…) or else he would be like an unfettered camel that walks in the dark; he would not be immune to falling.