Final answer:
Hamlet's play is set on an inevitable course due to a combination of elements, specifically Hamlet's tragic flaw, which primarily drives the play to its tragic conclusion.
Step-by-step explanation:
The play Hamlet is set on a course of inevitability not by a single action, but rather a combination of several elements which include the appearance of the ghost, Hamlet's tragic flaw, Claudius's ascension to the throne, and the death of King Hamlet. Each of these elements contribute to the unfolding drama, but it is Hamlet's tragic flaw, as described by Aristotle's concept of hamartia, that truly sends the play on its inevitable course. This flaw, which could be interpreted as his indecisiveness, his excessive contemplation, or his inability to act, ultimately leads to the play's tragic ending. Furthermore, the ghost's appearance sets the revenge plot into motion, Claudius’s ascension creates the initial conflict, and the death of King Hamlet provides the impetus for the story. However, it is Hamlet's internal struggles, stemming from his tragic flaw, that drive the play forward and seal its tragic fate.