Modernism and post-modernism are two aspects of aesthetic modernity reflecting some of the spiritual crises of the western civilization as resistance against the scientific modernity. These two are similar or the same to each other in seeing the modern world as fragments and discontinuities with pessimistic tone, the reality as relativity, and the language as lack. By contrast, many differences between the two can be seen as well. For example, modernism reflects Elite's taste of high culture while postmodernism is impatient with Elite's taste of ideas. And also, modernism hands down humanism and enlightenment while postmodernism rejects the so-called humanism and enlightenment. More likely than not, however, the foremost difference will be that modernism has the spirit of betterment by a kind of stoic attitude through self-criticism hoping for the birth of the hero who searches for the spiritual father, while postmodernism reflects a kind of Epicurism emphasizing 'seize the day' by accepting the commercial, technological and scientific values. It follows that modernism tries to expand freedom of more people through digging inner reality while postmodernism tries to expand equality of more people through de-constructing the concept of hierarchy of the western civilization. I think that Seamus Heaney's Seeing Things is characterized by the combination of modernism and post-modernism: his poetry contains the characteristics of modernism in respect that it continuously reflects the pursuit of tradition. At the same time, it includes post-modern aesthetics in respect that Squarings of Seeing Things transforms the concrete into the abstract by de-constructing some of the fixed meanings, from which readers can enjoy the entire freedom. My last conclusion is that Seamus Heaney's Seeing Things reflects not only his pursuit for the past tradition but also his desire to de-construct it. In brief, his poetry reflects some ambivalence: the search for the father and killing him, waiting for Godot and searching for light, freedom, equality and song.