because he was highly literate. Instead, an historical example of the embrace of technological assumptions happened with the Western world, which, heavily influenced by literacy, took its principles of "uniform and continuous and sequential" for the actual meaning of "rational." McLuhan argues that media are languages, with their own structures and systems of grammar, and that they can be studied as such. He believed that media have effects in that they continually shape and re-shape the ways in which individuals, societies, and cultures perceive and understand the world. In his view, the purpose of media studies is to make visible what is invisible: the effects of media technologies themselves, rather than simply the messages they convey. Media studies therefore, ideally, seeks to identify patterns within a medium and in its interactions with other media. Based on his studies in New Criticism, McLuhan argued that technologies are to words as the surrounding culture is to a poem: the former derive their meaning from the context formed by the latter. Like Harold Innis, McLuhan looked to the broader culture and society within which a medium conveys its messages to identify patterns of the medium's effects. "Hot" and "cool" media In the first part of Understanding Media, McLuhan also states that different media invite different degrees of participation on the part of a person who chooses to consume a medium. Some media, such as film, were "hot" - that is, they enhance one single sense, in this case vision, in such a manner that a person does not need to exert much effort in filling in the details of a movie image. McLuhan contrasted this with "cool" TV, which he claimed requires more effort on the part of viewer to determine meaning, and comics, which due to their minimal presentation of visual detail require a high degree of effort to fill in details that the cartoonist may have intended to portray. A movie is thus said by McLuhan to be "hot", intensifying one single sense "high definition", demanding a viewer's attention, and a comic book to be "cool" and "low definition", requiring much more conscious participation by the reader to extract value. "Any hot medium allows of less participation than a cool one, as a lecture makes for less participation than a seminar, and a book for less than a dialogue." Hot media usually, but not always, provide complete involvement without considerable stimulus.