Isotopy consists in the permanence of contextual features ("classemes"), whose variations, instead of destroying the unity of the text, serve to confirm it. The features in question are thus redundant, in the sense that they are repeated all through the text, assuring its coherence as well as a single interpretation. More recently critics argue that one text may contain multiple isotopies, each one giving rise to a different coherent reading, allowing, therefore, multiple interpretations. Isotopy is therefore a critical strategy that avoids the forced unity of New Criticism yet allows a text to “stay together,” rather than deconstruct into so many ironies there is no meaning as the New Critics understood meaning to exist within a text. See the site below for a fuller discussion. You will need to provide a fuller quotation (and contextualize it) for me to help you further.