How could it be argued that John Locke's philosophy is superior to that of Thomas Hobbes?
Both John Locke and Thomas Hobbes argued that civil society and government were the result of a social contract between people. Hobbes thought that in the absence of government, what both men called the "state of nature," men would live in a state of constant warfare, with the result being that life was "nasty, solitary, brutish, and short." As a result, they contracted with themselves to create an authority that they all agreed to obey. The contract, then, was not between the people and their rulers, but among themselves. Hobbes argued that this government could only fulfill its constituted purpose by the exercise of absolute authority over the people.
While it is perhaps too subjective to declare that Locke's understanding of the social contract is "better" than that of Hobbes, it is certainly more consistent with a modern understanding of civil liberties and the relationship between people and their governments. Locke argued that the social contract was created out of a need to protect property as well as basic rights. Because government was created by a decision made by free people, it could only properly govern by their consent. This clearly was a constraint on its power that is not present in the thought of Hobbes, and Locke took this idea even further, positing what amounted to a right of revolution on the part of people whose governments did not respect their rights:
there remains still in the People a Supreme Power to remove or alter the Legislative, when they find the Legislative act contrary to the trust reposed in them. For all Power given with trust for the attaining an end, being limited by that end, whenever that end is manifestly neglected, or opposed, the trust must necessarily be forfeited, and the Power devolve into the hands of those that gave it, who may place it anew where they shall think best for their safety and security.
So while Hobbes and Locke both articulated a theory based on a social contract, Locke argued that this contract provided a theoretical basis for fundamental liberties that we recognize as fundamental to modern society. Hobbes did not believe that governments should abuse their powers, but he also did not believe that the idea of a contract imposed any limits on government. Ultimately (or at least so far) Locke's ideas, which were not really formed in opposition to Hobbes as much as to divine right theorist Robert Filmer, became far more relevant to modern ideas about the relationship between the state and the people.