Emily Dickinson reveals her attitude toward death in "Because I Could not Stop for Death." She treats Death like a courteous and friendly person who does her a favor by bearing her away to the afterlife. She has a hopeful attitude that views death as a passageway to immortality. In fact, immortality is another guest in the carriage into which Death invites the poem's narrator.

The carriage held but just Ourselves —
And Immortality.

This is the type of hopeful attitude that Dickinson exhibits toward death in her poems.

Whitman shows greater grief when it comes to death. In "O Captain! my Captain!," the narrator bemoans the loss of the captain of a ship. The grief is heightened by the comparison of death to the victory that the rest of the crew is experiencing.

From fearful trip the victor ship comes in with object won;
Exult O shores, and ring O bells!
But I with mournful tread,
Walk the deck my Captain lies,
Fallen cold and dead.

Both Whitman and Dickinson present death not as a final ending point, but as something that can be transcended. To explore this, let us look at two oft-quoted passages from each poet.

Here is an excerpt from Dickinson:

Because I could not stop for Death—
He kindly stopped for me—
The Carriage held but just Ourselves—
And Immortality.

First, death is personified. Death is a character (as evidenced by "he") who is seemingly driving a carriage. Initially, the scary abyss that is death is made human, companionable, and subservient. Also in the carriage is a third character, Immortality. Immortality is the ability to live forever or to survive death. For Dickens, death is not a fearful entity. Death is a common occurrence, intrinsically paired with immortality. It is an idea that points to common adages today, such as "In death, there is life."

From Whitman, let us consider the epigraph to "Leaves of Grass":

Come, said my Soul,
Such verses for my Body let us write, (for we are one,)
That should I after death invisibly return, 
Or, long, long hence, in other spheres,
There to some group of mates the chants resuming,
(Tallying Earth's soil, trees, winds, tumultuous waves,)
Ever with pleas'd smile I may keep on,
Ever and ever yet the verses owning--as, first, I here and now,
Signing for Soul and Body, set to them my name. . . 

In this epigraph, Whitman directly addresses the function of his writing as it relates to his own mortality. He is writing as a way of marrying his soul to his human body in order to propagate his own life. As a result, when others, "some group of mates," goes on chanting his rhymes, he may keep on with a "pleas'd smile." In essence, when we breathe life by reading Whitman's words today, we breathe life into him.

Thoreau once remarked that

....The actual object which one man will see from a particular hill top is just as different from those another will see as the beholders are different; we can not see anything until we are possessed with the idea of it.... and then we can hardly see anything else.

Certainly, both Walt Whitman and Emily Dickinson were "possessed with the idea" of Nature, and they took it completely "into their heads." 

Walt Whitman

• admires and respects Nature
• perceives Nature as teacher
• considers himself as a part of Nature
• revels in Nature, spending time in it joyfully

Whitman wished to embrace everything as liberally as he perceived Nature doing, feeling one's way to knowledge, rather than attempting rationalization. Like Dickinson he closely observed Nature with deep respect. One of his poems that explicates lessons learned from Nature is Whitman's rather lengthy poem, "When Lilacs Last in the Doorway Bloom'd," in which he observes the rebirth of nature in the perennial, the lilac. He extrapolates this rebirth and applies it to the fallen soldier, perceiving his rebirth through others. In this way, the poet consoles himself over the tragic loss of life that the soldier has suffered.

When lilacs last in the dooryard bloom’d,

And the great star early droop’d in the western sky in the night,

I mourn’d, and yet shall mourn with ever-returning spring.

Ever-returning spring, trinity sure to me you bring,
Lilac blooming perennial and drooping star in the west,
And thought of him I love....

Emily Dickinson

• feels the necessity for Nature
• recognizes a profundity in Nature
• finds harmony with Nature
• finds Nature a source of beauty and joy
• finds it fascinating
• finds that the perception of beauty in nature is subjective

Perhaps better than anything to explain Dickinson's feelings and perception about Nature are her own words contained in this poem:

"Nature" is what we see—
The Hill—the Afternoon—
...Nay—Nature is Heaven—
Nature is what we hear—
The Bobolink—the Sea—
...Nay—Nature is Harmony—
Nature is what we know—
Yet have no art to say—
So impotent Our Wisdom is
To her Simplicity. 

Both Whitman and Dickinson found in Nature a source of joy, beauty, harmony, an image of the supernatural, and a certain fascination. Certainly, they found many private and profound experiences.