@hobbitsubculture, thanks for your amplification. I understand your reasoning, and I still disagree. We say “Mom and Dad” when we use them as names (they’re called “kinship names” in the Chicago manual, section 8.39) and we also say “my mother and my father.” They refer to the same individuals, but because of the status of the word as proper or common (and not our regard for or interpretation of what it represents) we treat them differently.
The proper nouns get caps and the common ones don’t. A common noun does not stand for a proper noun. A pronoun stands for a noun.
About the seasons, Chicago (8.94) says:
Days of the week, months, and seasons. Names of days and months are capitalized. The four seasons are lowercased (except when used to denote an issue of a journal).
You will also find them lowercased in the dictionary.