It isn’t difficult to conceive of Tithonus’s plight as a mythological presentation of elder experience, particularly in the present age, when health care has afforded the aged remarkable prospects of survival but little in the way of youth reclamation.  Absorption in the monologue promotes an empathic understanding, on the part of the young, of suffering in the very old. On Tithonus’s account, this suffering includes the experience of beauty as little more than an irretrievable memory.  For readers, the anguish of the empathic insight is heightened by the euphony of Tennyson’s verse.  Tithonus addresses Aurora—the dawn of a new day—as a lover; but her return is always a cruel reminder of his persistent human diminishment before her and of all that is now gone:          
  

A soft air fans the cloud apart; there comes            
A glimpse of that dark world where I was born.
Once more the old mysterious glimmer steals
From thy pure brows, and from thy shoulders pure,            
And bosom beating with a heart renewed.            
Thy cheek begins to redden through the gloom,
Thy sweet eyes brighten slowly close to mine,
Ere yet they blind the stars, and the wild team
Which love thee, yearning for thy yoke, arise,            
And shake the darkness from their loosened manes,
And beat the twilight into flakes of fire.  (ll. 32-42)

While the condition of the speaker encourages us to draw analogies to elder experience, the more fundamental emotional contemplation probably relates to debilitating grief.  Tennyson wrote the first version of the poem when he was in his early 20s, shortly after the death of his beloved friend, Arthur Hallam.  In some ways, the poem is a bitter, despairing rejection of William Wordsworth’s encouragements to seek healing in through exercises of memory.  At the limit of aging or of grief, Tennyson responds, memory is only a tortuous reminder of all one can no longer have.            

In the poem, as Tithonus makes use of his memory, he echoes—in profound anxiety—the adage of the human community that “The Gods themselves cannot recall their gifts” (l. 49), in which case, Aurora cannot take back the immortality she has bestowed.  As Tithonus uses his memory, though, the word “recall” (in the adage) strikes him, it seems, as a double-entendre (as critic Herbert Tucker has recognized)—related to memory as well as taking back.  Following the insight, Tithonus launches once more into recollection, suspecting that he is discovering a difference between Aurora and him: if he is able to “recall,” then he cannot be a god and must be mortal.  The excruciating irony here, however, is that as he persists in exercising his recollection, he re-asserts his human being, renewing his human life and contributing, therefore, to the realization of his immortality.  He proves complicit with Aurora in preserving the life from which he hopes to be delivered.            

The poem is devastatingly dark, but readers gain from it an experience of the lingering pain of mourning’s inescapability.  The lines of Tithonus addressing the ever-returning day are surely some of the finest in the language, capturing as they do the state of the aged-in-demise or of those in deep mourning:  
   

Thy strong Hours indignant worked their wills,            
And beat me down and marred and wasted me,            
And though they could not end me, left me maimed            
To dwell in presence of immortal youth,            
Immortal age beside immortal youth,            
And all I was in ashes.  (ll. 18-23)