A person who listens to old goth music (From the 80s), like Deathrock (Christian Death, Alien Sex Fiend, Specimen), Post-Punk (Bauhaus, Siouxsie and The Banshees, Joy Divison), Gothic Rock (The Sisters of Mercy, Fields of The Nephilim, Rosetta Stone) and maybe some New Wave (Depeche Mode, Duran Duran, Soft Cell), or anything related to the Batcave.
Old School aesthetics are punkish and cheesie, dark and sometimes elegant or sofisticated, but you don't have to dress goth to be goth.
They have no philosophy, nor a lifestyle, the only thiing that makes them a subculture is the music. Metal, Nu Metal, Industrial, EBM, or related genres are not included. Psychobilly, Horror Punk, Darkwave, New Wave and No Wave are related genres to goth, but generally are not considered goth, except for some Darkwave (Sopor Aeternus) and No Wave (Lydia Lunch) bands.
Goth music is not only music from the 80s, we have many groups from the 90s and 00s making goth music, like Naughty Zombies, Cinema Strange, Diva Destriuction, Joy Disaster, Faith and The Muse, Bat Attakk, London After Midnight, Two Witches, Frank The Baptist, All Gone Dead, etc...
Guy 1 - What subculture do you belong to?
Guy 2 - I'm an old school goth, I listen to Christian Death and Siouxsie.