In what ways do Hamlet's reactions to the skulls in the graveyard seem to suggest a change in his outlook?gravedigger's scene

When Hamlet first encounters the gravediggers, his
reaction is one of disbelief at the treatment of the
dead:

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Has this fellow no feeling of his
business, that he
sings at
grave-making?

He
goes on to say the following:

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That skull had a tongue in it, and could
sing once:
how the knave jowls it to the ground, as if it
were
Cain's jaw-bone, that did the first murder!
It
might be the pate of a politician, which this
ass
now o'er-reaches; one that would circumvent
God,
might it
not?

Hamlet is
questioning the actions of the gravedigger, but here, one can see that he is starting to
think of humanity and the fact that all of these skulls are human and were living once.
He's beginning to see that the skulls represent what everyone becomes once they
die.

What really makes him realize this is when he sees
Yorick's skull. Because he knew Yorick, he can make the connection to the rest of
humanity and himself. Eventually, he references Alexander the Great
asking:

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Dost thou think Alexander looked o' this
fashion i'
the
earth?

This
suggests a change in his outlook in that he's realizing that death comes no matter what.
He's starting to see that his life isn't worth preserving and that he can and must risk
it in order to avenge his father's death. Once he sees that the gravediggers are digging
Ophelia's grave, he has nothing to live for.