When we say 'secularism', it is often understood in different ways by different people. For example, in India there is this idea among some people that secularism entails respect of all religions. So some these folks say that no one should say this religion is bad/wrong; people need to accept that all religions are equally valid and no religion is more correct than others. Now this is a wrong understanding of secularism.
In order to remove confusion, we need to differentiate between political secularism and social secularisation. Let me explain what these mean.
Political secularism does have some sense of respect of all religions. But what is meant here is that the state should not discriminate any citizen on the basis of religion; the state should not say people of this religion cannot vote or people of that religion cannot have access to justice in the Court etc. Political secularism implies that the state is not going to discriminate any citizen on the basis of his or her religion. (As an individual I might say this belief of religion A is wrong or that practice of religion B is morally bad. But that's my opinion, not the state's opinion. As part of freedom of conscience that any citizen has, I can have my negative or positive opinion about this religion or that religion. But the state is not going to discriminate religious believers on the basis on his or her religion.) This is an essential aspect of political secularism.
But political secularism also implies separation of religious institution and state. Religious leaders will hold the rein of power in religious institution; while political leaders will hold the rein of power in political institution. This is the second aspect of political secularism.
The third aspect of political secularism is that citizens have freedom of religion. This is closely related to the second point. This says that since the state has no state religion, as religious institution and state are separate, citizens are free to choose this religion or that religion or no religion. The state will not dictate citizens' religious belief.
Social secularisation on the other hand is the transformation or state of society that is devoid of religious values. For example, if the atheists are successful in converting all the citizens into their way of belief, then that society will be a highly secularised society.
If the state is politically secular, won't the society also be a secularised/irreligious one? Not necessarily. Apart from the state, there are other institutions. One is family. The state can't dictate what religion a family must follow. So families can choose to be religious. Also there is civil society, and this includes clubs, churches, NGOs, Gurudwara etc. These civil society need not be irreligious; they can be religious too. Freedom of religion that political secularism offers allows other institutions to be religious within the bound of public order.
