John Locke is most noted for his writings concerning:

John Locke is most noted for his writings concerning human rights, particularly his ideas about natural rights and the social contract. Locke argued that individuals are endowed with inherent rights such as life, liberty, and property, which governments are created to protect. His philosophical contributions laid the groundwork for modern democracy and the understanding of individual rights.

Locke's influence is particularly evident in his works like "Two Treatises of Government," where he contended that the legitimacy of government comes from the consent of the governed and that it is the duty of the government to safeguard the rights of its citizens. This conception of human rights has had a profound impact on political thought and the development of constitutional democracies.

In contrast, while the other choices touch upon various significant topics, they are not primarily associated with Locke's main philosophical contributions. His works do not specifically focus on free enterprise as a concept nor do they delve into the scientific method, which is more commonly linked to figures like Francis Bacon or Galileo. Additionally, while Locke did address issues related to slavery and property, these discussions are not the central focus of his philosophical legacy in the same way that his exploration of human rights is.