The speaker of this poem to all intents and purposes can be taken as being Tennyson himself, as he writes an intensely personal poem describing his struggle to come to terms with the death of his friend, Hallam. This explains the way in which so many of the sections of this brilliant poem that encompasses such themes as grief, death, faith, science and religion focus on the speaker's struggle to make sense of life now that his best friend has died. Consider the following stanza from section 7 of the poem:
He is not here; but far away
The noise of life begins again,
And ghastly thro' the drizzling rain
On the bald street breaks the blank day.
The speaker is a man who finds himself struggling with the way that life seems to continue to carry on but he himself cannot move on. So greatly is he impacted by his friend's death that he is unable to begin life again. Note the alliteration of the "b" sound in the final line of this stanza that emphasises how terrible he finds the coming of day and the hustle and bustle of "normal" life in his state of grief.