Here's why:
* Participles are verb forms that act as adjectives or adverbs. They typically end in -ing (present participle) or -ed/-en (past participle).
* Examples: "Running water", "the broken vase"
* "Appear" is a present tense verb, indicating an action that happens now. It's not acting like an adjective or adverb.
However, "appear" can be used in verb phrases with participles:
* "Appearing" (present participle) - "The singer is appearing tonight."
* "Appeared" (past participle) - "The ghost appeared in the mirror."
In these cases, "appearing" and "appeared" are participles, but "appear" itself is not.