"The Modern Theme", originally published in Spanish as "El tema de nuestro tiempo", and first published in English in 1933, is a work on philosophy and sociology by Spanish philosopher Jose Ortega y Gasset. As the title suggests, the main point of this work is to try to describe the defining trait of modernism.
The medium and the message are similar here, because Ortega believes that the main idea of modern times is that it could not be described from a single objective viewpoint, and he makes his case in a somewhat scattered way, including many sociological and historical allusions that would be seen as somewhere between overly broad and insulting to the contemporary reader. He concludes that neither rationalism nor "relativism" (which might seem closer to "romanticism") can provide a complete view of human life:
Neither rationalist absolutism, which keeps reason but annihilates life, nor relativism, which keeps life but dissolves reason, are possibilities.
Which seems like a fairly unobjectional statement in general, although I am not sure I would say it is a summary of modernism. The problem arises in how he demonstrates the growth of reason:
When we turn to Asiatic history, we invariably seem to be watching the vegetal growth of a plant, of an inert being, without sufficient resilience to defy destiny.
Even though the word "Asiatic" is not insulting in Spanish, statements like this, that the rest of the world is tradition-bound and that the ability to look at the world "rationally" was something that Europeans (and specifically Socrates) invented is one of his major ways he advances his worldview. That society advances through a tension between abstract rational principles and real-world concerns is a pretty reasonable thing to say, to say that it was something that only Europeans had discovered shows an ignorance of other cultures. (And also is ironic to me, because as an American, a person from a culture that has irony, I am often struck by the literal credulousness that Europeans have in institutions).
But the major problem with this book for me was not the insulting nature of these sociological observations, but just that it rested on sociological observations at all. Ortega makes some good points, but there is not an idea here that represents a shift of paradigm. It did not produce a new idea, but rather talked about old ideas, in this case, the perennial issue of reason versus romance. This was Ortega's point in the book---that real circumstances, and not monolithic ideas, were how we developed, but this book has a problem I have pointed out: that post-Kant, very little metaphysical ground remains to be explored, and "philosophy" becomes "commentary" and "thought", random perambulations on several related topics (some of which are still valid, some of which have not aged well), but not providing any core insight into the world.