As we have seen in recent years, free speech is endangered by a society that is more sensitive and unable to tolerate opinions contrary to its own merely because they are perceived as offensive.

The universal right to free speech is a cornerstone of any liberal democracy. When instead of giving space to refute ideas with arguments, we censor them, we displace them to a position where they cannot be proven wrong and their thinkers become martyrs.

When the focus is placed on "protecting" people from potentially offensive or uncomfortable ideas, we run the risk of giving the status quo authority to censor ideas on this basis, a precedent that can be costly.

Who decides which ideas are valid and which are not? We must be very careful, because once we give someone this power to judge the validity and correctness of any speech, we are unlikely to be able to reverse this authority once it is established.

The range of opinions that are considered acceptable by society at a given time. Their tendency to vary with time and place should tell us something about the cultural specificity of ethical norms.

There are those who aspire for the Overton window to shrink to the size of a picture window, and for the opening that remains to fit comfortably within their prejudices.

Unfortunately, in recent years there has been an increasing number of cases of censorship on university campuses because students claimed they felt "offended".

A place that was once the place where world-changing ideas emerged is becoming less open to free speech.

Those who are unwilling to listen to ideas that might shake their most established principles run the risk of remaining on a lateral learning curve.