Seamus Heaney's "Digging" refers both to the menial labor performed by the speaker's ancestors, which forms the ostensible subject of the poem, and the labor of writing poetry in which the speaker himself is engaged. The poem expresses the speaker's awe at and distance from the hard work and implicit masculinity of previous generations of men, and simultaneously claims a similar usefulness and importance for his own literary vocation.
Structurally, the poem begins and ends by calling our attention to the pen in the hand of the speaker as he writes a poem—presumably the one we're reading. These references bracket the main action of the poem—the physical work of first the speaker's father and grandfather. Heaney's description of their digging is replete with imagery that emphasizes the difficulty of their tasks; the men are "straining" (l.6), "stooping" (l.8), "nicking and slicing" and "heaving" (l.22). Perhaps even more importantly, their labor has tangible results. The speaker remembers the tubers' "cool hardness in our hands" as his father dug in the potato fields, and his description of his grandfather's work cutting turf in the peat bog calls on our other four senses with his evocation of "[t]he cold smell of potato mould, the squelch and slap/ Of soggy peat, the curt cuts of and edge" (ll.25-26). In throwing the reader into a complete sensory world, the poem insists on the sheer physicality of the work, and reminds us of our own embodiment, too. It is significant that both of the tasks described provide for the physical needs of the men's families - the potatoes will feed them and the blocks of peat will fuel their fires through the winter.
Through both their manual labor and their role as providers, these men have firmly established not only their usefulness, but also their masculinity. The speaker remembers, "My grandfather cut more turf in a day/ Than any other man on Toner's bog" (ll.17-18), clearly using his work as the criteria for evaluating his manliness. Furthermore, the jobs performed by his father and grandfather are both quintessentially Irish activities. Their lives and work are firmly located within a specific place and a definite cultural identity that is inseparable from their masculinity. Indeed, the notion of a strong heritage is emphasized when the speaker says his father "could handle a spade./ Just like his old man" (ll.15-16). This is clearly a family tradition.
The poem implicitly presents us with a question: What is the speaker's relationship to this heritage of Irish masculinity and the meaningful work on which it is based? After all, he is present in the fields only as a spectator, a witness to the work of others who only marvels at the products of their labor or brings a refreshing drink. As an adult, he appears in our poem holding not a spade, but a pen, doing literary work that in many ways might appear to be a far cry from the physical labor of his forebears. He himself admits, "I've no spade to follow men like them" (l.28), as if acknowledging that his artistic work (not only removed from the fields of Ireland but actually revolving around the intricacies of English, the language of the colonizers), creates a break in his cultural lineage. Yet this is where the second meaning of the poem's title comes in. Heaney's "Digging" refers not only to literal digging in the dirt, but to the metaphorical digging, sifting, and unearthing performed by the poet himself in the very act of writing the poem. Despite his professed modesty, the speaker actually claims equal value for his poetic labor.
As noted earlier, he both begins and ends the poem by focusing on the feel of the pen in his hand, reminding us that writing, too, is a physical act. The pen itself is simple and "squat" (ll.2, 30), a legitimate instrument as opposed to merely a learned accessory. Indeed, not only will he use it to dig, but it is also like a gun (l.2), carrying with it the possibility of resistance and rebellion in response to the history of colonial exploitation so poignantly symbolized by his father's work in the potato fields (recalling the potato famine of the 19th century) and his grandfather's work in the peat bogs (which will function in Heaney's poems as a site for unearthing painful truths about the social and political past).
Yet the speaker does more than merely claim authority for his labor through metaphor. The poem itself performs the digging motions of Heaney's ancestors. Just as he remembers his father "[s]tooping in rhythm through potato drills" (l.8), so the poet creates his own rhythm through the complex interplay of consonants throughout the poem. For example, the line, "He rooted out tall tops, buried the bright edge deep" (l.12) repeats "t," "b," and "d" sounds whose alternating crispness and roughness remind us once again that we are in a sensory universe, but also evoke the bite of the shovel cleaving the earth and the thud of the dirt being dumped onto a mound. In other words, the poem sounds like digging. Furthermore, the structure of the poem reenacts the digging process. Beginning at his window in the present, the speaker takes us back in time first to his father's labor and then to his grandfather's, moving into the past and then even further back, just as his grandfather dug beneath the surface of the bog, "going down and down/ For the good turf. Digging" (ll.23-24). Just as his ancestors unearthed resources vital to their survival, so the speaker, having reconnected with his Irish past through the excavation performed by his poem, now has the tools necessary to productively represent his culture by extending its values into the literary arena. If the product of his work is not strictly tangible, it is indeed very real.