According to the Koran, ‘Allah’ is one and no other god can be associated with him. This concept was most likely adopted from the South Arabian moon-god ar-Rahman (the Merciful), whose name was later adopted by Muslims as one of ‘Allah’s’ titles. C. C. Torrey states:
The South Arabian inscriptions have brought to light a highly interesting parallel. In a number of them there is mention of the God, who is styled ‘the Rahman’ (Merciful). A monument in the British Museum... is especially remarkable. Here we find clearly indicated the doctrines of the divine forgiveness of sins, the acceptance of sacrifice, the contrast between this world and the next, and the evil of ‘associating’ other deities with the Rahman.
The theological concept of shirk, however, goes beyond the simple denial of ‘Allah’s’ unity. It can also be a superficial piety of Muslims who fulfil their prayer obligation due to peer pressure, force of habit, or some other hypocritical reason. However, there exist two relevant concepts called ‘lesser shirk’ (al-shirk al-asghar) and ‘hidden shirk’ (al-shirk al-khafiy), in the depths of the human’s soul.
Muhammed probably committed this interpretation of shirk when he assumingly associated three Arabian goddesses with ‘Allah’, which is called the ‘affair of the Satanic verses’. Muhammed’s troubles had started when Abu Jahl, one of his most fierce adversaries in Mecca, came to him and demanded that he would stop cursing their gods. Although Muhammed hated polytheism, he had a great respect for the Kaaba, the Meccan place of idol worship, and, at this stage, could not afford to invoke any further hostility. Thus he declared:
Do not revile the idols which they invoke besides Allah, lest in their ignorance they revile Allah with rancour. Thus have We made the actions of all men seem pleasing to themselves. To their Lord they shall return, and We will declare to them all that they have done.
According to Ibn Ishaq, Muhammed then refrained from cursing the Meccan idols, but called them all by the same name, ’Allah’. Muhammed had now merged all the 300-some idols at the Kaaba into the city’s chief deity, calling all of them by the same name.
Thus Islam is the religion of ‘oneness’ as opposite to shirk, which literally means to ‘join together’ or ‘participate’. That implies, that there is no other true religion, and to Islam all men should surrender in submission, in order not to commit shirk and become zindiqs (those who reject ‘Allah’s’ oneness) kafirs (infidels, lit. unbelievers; kufr=unbelief) or mulids (atheists). The Muslim author Fatima Mernissi discusses these terms and, after having declared the opposition of islam and shirk, states:
Shirk is the most appropriate word for translating the word “freedom” in Article 18 of the Universal Declaration for Human Rights, which is posed as an ideal to be attained. “Everyone has the right to freedom of thought, conscience, and religion; this includes freedom to change his religion...”
Thus, if shirk, as the opposite term for islam, stands for freedom of thought, conscience and religion, it is not surprising that Islam has had some problems with facing the Western way of thought, with its democracy and varieties of ‘freedoms’.