What does Hamlet no longer value and thus obeys the summons of the ghost?what does thus obey summons mean
In Act 1, scene 5, after seeing and speaking to the ghost of his dead father, Hamlet, with obvious conviction says:
Yea, from the table of my memory
I'll wipe away all trivial fond records,
All saws of books, all forms, all pressures past,
That youth and observation copied there;
And thy commandment all alone shall live
Within the book and volume of my brain,
Unmix'd with baser matter.
What he is saying is that he will think of nothing but the Ghost and the revenge the Ghost has asked him to perform. And there is not just a little irony here: Hamlet says he will have no other thoughts, no thing he has read or remembered from the past or been bothered by, no thing will be in his mind except the thing he has to do. Well, that's all terrific, except what is asked of him takes very little thought; it demands action. Unfortunately, Hamlet, in this little speach, talks about what he will think about and not what he will do. Indeed, he should not have said a word. Rather, he should have taken his sword and straightaway descended the battlements and killed King Claudius in the courtyard below. But he doesn't... instead, he thinks about what he should be thinking about.
Another Shakespearean character, Macbeth, said it adroitly and succinctly:
Words to the heat of deeds too cold breath gives.