Calling secularism (the insistence on separation of church and state) a religion should be instantly recognized as an oxymoron, analogous to claiming that bachelors can be married. Sadly this is not the case, and it has become far too common for critics of secularism to claim that it's a religion which is being improperly supported by the government. Examining the characteristics which define religions as distinct from other types of belief systems reveals just how wrong such claims are.
Perhaps the most common and fundamental characteristic of religions is the belief in supernatural beings — usually, but not always, including gods. Few religions lack this characteristic and most religions are founded upon it. Does secularism involve belief in supernatural beings like gods? No — secularism neither encourages nor discourages it. Secularism can be adopted by theists or atheists, regardless of their position on the existence of the supernatural.
Differentiating between sacred and profane objects, places, and times helps religious believers focus on transcendental values and/or the existence of a supernatural realm. Many atheists probably have things, places, or times which they consider "sacred" in the sense that they are venerated in some way. Does secularism involve such a distinction? No — it neither encourages nor discourages it. Some secularists may believe that some things are sacred and others won't.
If people believe in something sacred, they probably have rituals associated with it which are considered sacred. An atheist who holds something as "sacred" may engage in some sort of ritual or ceremony. As with the very existence of a category of "sacred" things, however, there is nothing about secularism which either mandates such a belief or excludes it. Some secularists participate in rituals and some don't; there are no secularist rituals.
Most religions preach some sort of moral code which is typically based upon whatever transcendental and supernatural beliefs are
fundamental to that religion. Thus, for example, theistic religions typically claim that morality is derived from the commands of their gods. Secularists have moral codes and some believe that those codes have supernatural origins, but this isn't a "doctrine" of secularism nor is it inherent in secularism.
Perhaps the vaguest characteristic of religion is the experience of "religious feelings" like awe, a sense of mystery, adoration, and even guilt. Religions encourage such feelings, especially in the presence of sacred objects and places, and the feelings are typically connected to the presence of the supernatural. Some secularists surely experience such feelings and others surely don't. There is nothing about secularism which promotes them or relies upon them in any way.
Belief in supernatural beings like gods doesn't get you very far if you can't communicate with them, so religions which include such beliefs naturally also teach how to talk to them — usually with some form of prayer or other ritual. Some secularists believe in a god and therefore probably pray; other secularists don't. Because there is nothing about secularism which encourages or discourages belief in the supernatural, there is also nothing about it which deals with prayer.
Religions constitute entire worldviews and teach people how to structure their lives in relation to their worldview: how to relate to others, what to expect from social relationship, how to behave, etc. Secularists have worldviews, but they have all different worldviews and secularism itself isn't quite a worldview. It can be a complex political philosophy, but one that is narrowly targeted and which does not encompass wide segments of a person's life or form a basis for organizing one's life.
A few religious people follow their religion in isolated ways, but more often than not religions involve complex social organizations of believers who join each other for worship, rituals, prayer, etc. Secularists probably belong to a variety of groups, but not all the same groups. There are secularist groups, obviously, but they are not bound together by all the above because none of the above is inherent in secularism or even really a part of secularist philosophy.
Secularism was originally a non-religious philosophy focused on the needs and concerns of humanity in this life, not the possible needs and concerns associated with any afterlife. Today the concept of secularism, at least in the social sciences, is restricted to the idea that public and government institutions should be independent of the control of religious authorities.
Does it matter whether secularism is a religion? It must to those who keep making the claim, despite all evidence to the contrary and despite that calling secularism a religion is an oxymoron. Are they unaware of how the concepts are defined? Are they unaware that logical contradictions like this shouldn't be claimed?
I believe that this claim is made in order to suggest that secularism is at its heart a hypocritical position: secularism proposes that civil and religious power should be separated and that there should exist civil institutions outside the control of ecclesiastical authorities; if secularism is a religion, however, then secular institutions are necessarily religious and supporters of secularism are just trying to substitute their religion for more traditional faiths like Christianity.
Clearly this argument is false, buy why do people insist on making it? Doing so avoids the most substantive discussion about where the line between civil and ecclesiastical authority should be drawn. It would also allow someone to avoid admitting that they want to eliminate secularism and replace civil institutions with religious ones.
Calling secularism a religion misrepresents both concepts in a manner that actually hinders debates, decreases knowledge, and prevents people from engaging in substantive discussions about serious issues. There are legitimate disagreements and debates about the role of religion in society and the extent to which society and government should be secularized. None of these can move forward, however, so long as the conceptual waters are being deliberately muddied.
