The High Court has been told that the State is entitled to discourage suicide but is not entitled to stop a disabled person doing what an able-bodied person can do.
The submission was made by counsel for Wicklow woman Marie Fleming, 58, who is taking a landmark case to establish a right to end her life with assistance.
Senior counsel Brian Murray said the State was trying to do this by reference to a very general concept of the common good which was not being applied equally.
Mr Murray said suicide was not illegal yet Ms Fleming was prevented from ending her life because of her physical incapacity to do so.
He said previous cases had established the right to privacy, autonomy, self-determination and dignity which lie at the heart of Ms Fleming’s claim.
Those rights include the right to die with dignity, he said.
Mr Murray added it was unconstitutional and discriminatory if a person was to lose those rights enjoyed by those with the capacity to enjoy them.
It was wrong for the State's interest in the lives of people on some theory of natural law to override a person's free choice.
Ms Fleming was diagnosed in 1986 with MS and is in the final stages of the condition.
She is past the point where she could take her own life unaided but wants to establish the right to end her life with assistance.
She is challenging a section of the Criminal Law Suicide Act which makes is an offence to help someone take their own life.
Her lawyers argue the section of the act is contrary to the provisions of the Constitution and incompatible with the European Convention on Human Rights.