The functional view of the phoneme can be qualified as idealistic as it regards the phoneme as an abstract conception existing in the mind but not in reality, that is in human speech.
Distributional method is based on the phonological rule that different phonemes can freely occur in one and the same position, while allophones of one and the same phoneme occur in different positions and, therefore (поэтому, следовательно), cannot be phonologically opposed to each other.
pea – bee
/p/ /b/
rope – robe
Methods of phonological analysis
Semantic method is based on the phonological rule that can distinguish words when opposed to another phoneme or zero in an identical phonetic position.