In The Name of Allaah, The Most Merciful, The Bestower of Mercy.
Imaam As-Sadi [may Allaah have mercy upon him] stated:
The statement of many of the materialists (atheists) and those who blindly follow them is that “There should be freedom of thought, everyone should be free to hold the opinion he sees fit and the proposal he makes”. This has also manifested its great harm. Indeed, freedom of thought – giving everyone his freedom (i.e. based on desires) – has shown to be the very reason behind anarchy; rather that is its basis. Animals become better than them (i.e. humankind and Jinn) when they are given freedom in that which corrupts their morals and (sound) beliefs, and thus their deeds became chaotic. This is the reality in every country where freedom has been let loose and not restricted by the divine legislated restrictions that are in conformity with (sound) intellect, because the souls command evil, incline towards arrogance and insolence, and approach every desire whether it harms individuals and groups or not. Just as giving one the freedonm to do as he pleases unrestrictedly cannot remain, because if everyone was left with his freedom that he can murder, injure or hit, or take the wealth of the people or violate their honour, then indeed the state of affairs would have been corrupted, the world would be in anarchy, chaos, disturbance and great harm will occur; likewise, the freedom of thought has brought evil, and from its filthy fruits is dispensing with religion and the Messengers [peace and blessings of Allaah be upon them], rejecting what they brought and that which sound intellect indicates, such as the obligation of restraining and guarding oneself against the harmful affairs related to creed, morals and deeds.
And among the outcomes of freedom of thought are the statements heard from the atheistic and vile newspapers that shake the hearts of the people of sound intellect, and indeed they have done great harm to the beliefs and morals; rather it has harmed governments, groups and individuals. As for the Islamic legislation, then indeed it – and praise be to Allāh – came to alert the intellects and urge towards (sound) reflection on those affairs that are useful for one to reflect on, such as the signs Allaah has created in the creation and the signs conveyed in the divine revelation; pursues the sound paths of reflection and examining them, and thus it affirms the beneficial sciences and truthful understandings- urges towards every beautiful character, warns against every evil character and places a sound restriction on ideas, which if encroached will result in destructive things and various types of misguidance. If ideas are not restricted by sound intellects and religion – which Allāh has provided for the servants in which is the rectification of their affairs and perfection of their circumstances, then indeed they give birth to chaos and error, misguidance, misery, folly and insanity. [Ad-Dalaa’il Al-Qur’aaniyyah. page 22]