Wikipedia has a good short article on the distinction between negative and positive rights. "A negative right is a right, either moral or decreed by law, to not be subject to an action of another human being (usually abuse or coercion)." To use Justice Brandeis' famous phrase more broadly than he used it, negative rights are "rights to be left alone." All civilized legal systems beyond the village or tribal level have been systems of negative rights. For example, Anglo-American common law defines spheres of personal space which other persons must not invade -- especially spheres involving the body, residence, possessions, and property. The only way to create positive rights in traditional common law is to personally agree to them -- i.e. to make a contract.
The United States Constitution was drafted by people who, at least for amendments made before the 1930s, defined rights as negative rights. Thus, when the Constitution in the Fourteenth Amendment protects the "life, liberty, or property" and "equal protection of the laws" to "any person," it is referring to acts which government must refrain from doing, not to any positive duty of the government to act. The only time the government has a positive duty to act is when it has already deprived a person of liberty (e.g., prisoners, and arguably children compelled to attend public schools). Unfortuneately, the Court since the 1940s has departed sharply from this basci tenent of civilized law. It has read positive rights into the Constitution, thereby depriving citizens and other persons of negative rights to which we are entitled.