Legally speaking, the term 'public rights' is as vague and indefinite as are the terms 'public health,' 'public good,' 'public welfare,' and the like. It has no legal meaning, except when used to describe the separate, private, individual rights of a greater or less number of individuals.

In this quote, Lysander Spooner, an American legal theorist and abolitionist, critiques the vagueness and ambiguity of the term 'public rights' and other related terms like 'public health', 'public good', and 'public welfare'. Spooner argues that these terms lack a precise legal meaning and are often used in a vague, imprecise way that does not offer clarity in legal contexts. According to Spooner, these terms are not meaningful unless they describe the individual rights of a group of people, which, in his view, are fundamentally private rights.

Spooner’s statement suggests that when the government or legal systems invoke public rights, they are often doing so in a way that obfuscates the true nature of the rights being discussed. Rather than being a clear, collective legal concept, Spooner views public rights as a way of referring to the rights of individuals that are grouped together or framed in a broad, general manner. In his view, the use of these terms in legal discourse can serve to obscure or dilute the specific rights of individuals.

The origin of this quote lies in Spooner’s broader critique of the legal system and his philosophy of natural law. He was highly critical of the government's role in infringing on the rights of individuals, particularly in areas like slavery and constitutional law. Spooner believed in the primacy of individual liberty and property rights and was often skeptical of government language that could be used to justify the overreach of state power under the guise of promoting the public good.

Ultimately, Spooner’s quote reflects his belief in the importance of clear and specific legal definitions, especially when it comes to rights. He argues that vague terms like public rights should be carefully scrutinized, as they can easily be manipulated to justify actions that may not truly align with individual freedoms. His perspective calls for a more precise understanding of rights, where the distinction between public and private interests is clearly defined in legal contexts.