Eliot's position in twentieth-century English literature is due not only to the approach which he adopted o poetry, but also to his contribution as a critic.
The extract is taken from one of his most important essays and concerns Eliot's attitude to tradition and his conception of the impersonality of literature.
The essay deals with the value of tradition, in particular with the relationship between the work of the individual poet and that of the poets who wrote before him.
The thesis is not immediately expressed. Eliot begins saying what  tradition is not in his opinion. As a matter of fact he suggest to discourage tradition as following the ways of the immediate generation before. Eliot suggests that tradition involves the historical sense. For this reason he makes a digression about the historical sense. He writes that historical sense is the perception and awareness of the pastness

of the past in a writers' works. An innovative work of art can only come to life if it has to display the tradition of his bones. The historical sense is what makes a writer traditional.
Eliot goes one referring to the meaning of being poet or artist: his value has to be compared to dead artists' one. No artist has his complete meaning alone.
At this point of the essay Eliot expresses his thesis: a innovation makes you look at the past in a different way.
The ideal order among products already created is modified by the introduction of the new. The relations, values of each work of art toward the whole are readjusted in conformity between the old and the new.
It has been created an idea of simultaneous time. It is not lived in a deterministic way, facts are no read in causa-effect way, but in a simultaneous one.
The poet's awareness of this attitude will be aware of difficulties and responsabilities.

I never think about innovation like something that upsets previous products, but I have believed innovation like something that upsets future products. I like this other way of thinking.
I like also the connection between past and present and the links between them. I believe that events happened in the past bring some of our behaviour in the present about.