On the moral permissibility of pornography
An adage from Voltaire, a French philosopher, is one of the foundations of the permissibility of pornography: I disapprove of what you say, but I will defend to the death your right to say it. The adage is self-explanatory. In the same way that no one should be coerced to do something outside of his or her will, no one has the right to prevent someone of his or right mind from doing any thing that he or she prefers unless this should be done to prevent harm to others. Mill’s harm principle supports this justification when he said that an individual has absolute independence to do anything to him- or herself as long this concerns him- or herself alone.
On restriction of pornography
The restriction on pornography is rooted on the contrarian reasoning of offence principle (versus Mill’s harm principle), which argues that pornography has to be publicly restricted or prevented so as to avoid other non-consenting adults to be unwittingly or involuntarily exposed to it. This principle accepts that the voluntary and private consumption of any types of pornography will not harm others. However, there is a probability that displaying pornography in public may be tantamount to an “offensive nuisance” to those who do not consent or are involuntarily exposed to it. To simply this explanation, it is considered an offensive nuisance if some residents in a community play bad music loudly even during the holy hours of the morning.