The Canadian Constitution protects specific "fundamental freedoms"; these freedoms are seen as the core of Canadian liberty and are protected against governmental infringement at any level.
The fundamental freedoms are freedom of expression, freedom of religion, freedom of thought, freedom of belief, freedom of peaceful assembly, and freedom of association. These freedoms are seen as being the essential basis of a functioning democracy.
Despite their essential nature the fundamental freedoms are not without limits. Freedoms is not absolute especially when one freedom comes into conflict with another. Zechariah Chafee famously said, “Your right to swing your arms ends just where the other man's nose begins”. Freedom of expression does not justify child pornography and a religion that mandated human sacrifice would not be protected (at least for the sacrifice) under Canadian law.
That said, limiting fundamental freedoms is a tricky business – such limitations should only be made where there is a good reason. Over the years governments have tried to limit fundamental freedoms where such limitations are unnecessary and often wholly improper.
Disliking, for example, someone’s religion is not a legitimate basis to restrict religious freedom. In 1955, when Jehovah’s Witnesses were (for reasons that baffle me) widely disliked, the Supreme Court of Canada ruled that all religions have equal rights, based upon tradition and the rule of law; it did so in a Jehovah’s Witness case where police had raided a home where a religious service was being conducted, seized bibles and other religious paraphernalia, and disrupted the service despite not having a warrant and no charges being laid.
All that said, freedoms do have limits but those limits are closely circumscribed. The Canadian Constitution recognizes these limits explicitly saying:
“The Canadian Charter of Rights and Freedoms guarantees the rights and freedoms set out in it subject only to such reasonable limits prescribed by law as can be demonstrably justified in a free and democratic society.”
What this means is that a fundamental freedom can be limited if there is a defined law that sets a definite limit that can be understood. Such will not exist "where there is no intelligible standard and where the legislature has given a plenary discretion to do whatever seems best in a wide set of circumstances". Any limit has to be something that can be understood clearly; so a law that said “any disgusting photograph” would not be a valid limitation whereas a law that said “explicit pictures of persons under 18 engaged in sexual conduct are illegal” would almost certainly be valid.
Deciding whether there the defined limit is “demonstrably justifiable in a free and democratic society” is determined by considering both the purpose of the limitation and the means used. Specifically, if there is a limit on a fundament freedom which is prescribed by law that limit will be acceptable if the following test is met:
There must be a pressing and substantial objective; and
The means employed must be proportional
1. The means must be rationally connected to the objective
2. There must be minimal impairment of rights
3. There must be proportionality between the infringement and objective.
As can be seen, meeting the test of a legitimate limit to a fundamental freedom is difficult. But that’s exactly what we want – fundamental freedoms ought to be limited only where absolutely necessary.