Answer:
Both
Step-by-step explanation:
There are different clauses in this extract, linked to each other in different ways:
"Watterson has explained that Calvin was named after the sixteenth-century theologian John Calvin;"
In this case, "that Calvin was named after the sixteenth-century theologian John Calvin" is a subordinate clause which is indeed subordinated to the main independent clause: "Watterson has explained", by the use of "that". Thus, we have an example of subordination.
Then, we have the semicolon ";" in between the first complex sentence and the second one, which is "[previous sentence] ; likewise, Hobbes was named for another influential thinker, the seventeenth-century philosopher Thomas Hobbes." Here we have an example of coordination introduced by that semicolon.
IMPORTANT: "the seventeenth-century philosopher Thomas Hobbes." Is only a nominal phrase, since it doesn't contain any verb.