The first type of ambiguity is essentially that of a metaphor: when two people, objects or concepts are alike in some way, even though they may have different qualities otherwise. Comparison provides a given object with multiple meanings, allowing it to be interpreted in different ways even though it remains essentially unchanged.
The second type of ambiguity occurs when two or more different alternate meanings are used as one. That essentially means using two different metaphors at once, neither lessened nor invalidated by the comparison. These metaphors aren't at odds with each other as they may be in other types of ambiguity; they're simply different.
Separate ideas or notions can be expressed simultaneously in a single word, which constitutes the third type of ambiguity. The most obvious example is a pun, although it can also extend to an allegory or a cultural reference applicable to specific demographics, such as Biblical terms placed in an otherwise secular political speech. The key distinction is that the meanings appear simultaneously; in other types of ambiguity, they may act in conjunction or as part of the same phrase, but never at the exact same time.
The fourth type of ambiguity combines two disconnected or opposing ideas into a single conceit. They reveal complexities or conflicts within the mind of the author, and hence create ambiguity. Such complexities are not unresolvable, as they are in the seventh type of ambiguity, though their existence may be problematic and require considerable discussion to fully understand.
Sometimes, the author may not come upon a given idea until it enters his mind during the writing process itself. The idea may not be fully formed, and embody confusing or even contradictory tenets, yet it still appears as the words are laid on the page. Such fortunate confusion constitutes a simile, and the fifth type of ambiguity.
The sixth kind of ambiguity occurs in the mind of the reader. If the author says nothing or leaves his meaning intentionally vague, it falls to the reader to invent or suppose the meaning of the text. Since every reader is different, the resulting meaning often contains ambiguities.
The final form of ambiguity entails flat-out contradiction within the context of the text. Two or more concepts appear in the same piece, and remain unresolved despite their connection through the text itself. This differentiates them from complexities, which ultimately can be resolved. Such ambiguities illustrate a clear division in the author’s thought process: an unresolved tension that can’t be reunited without taking one side or the other.