If what Ellis says is true, then Derrida has illogically switched categories by substituting these words for Saussure's idea of contrasts. Switching categories in this manner is an informal logical fallacy and makes Derrida's argument logically invalid. That is why the immediate context of a word in a sentence or paragraph, or the immediate context of a scene in a film or play, usually determines its meaning. This is a general rule of all interpretation that Derrida and his gang ignore. By ignoring this rule, they clearly show the inherent fallacies of their whole theory.
Deconstructionism is part of a movement called poststructuralism.
Like deconstructionism, this movement has many problems with it. Poststructuralism builds on many ideas developed by structuralism, its precursor. Since, many of the most noteworthy structuralists seem to have thought that reality is unknowable and, therefore, we should stop trying to seek some ultimate truth or meaning to all things. I am skeptical of this extreme skepticism. According to Sturrock, the structuralists and poststructuralists don't like authoritarian interpretations, but their fuzzy-minded pluralism is just as authoritarian as any other system of interpretation.