Chat GPT-5 recently gave me this gem:

The Real Case for Tabs

  1. Tabs are the only true semantic indentation.
    • A tab means one level deeper. Nothing more, nothing less.
    • Encoding indentation with spaces hardwires a presentation choice into the file. That’s a category mistake.
  2. Tabs unlock flexibility beyond fixed widths.
    • You’re not limited to “tabs = 2 or 4 spaces.” Terminals can support arbitrary tab stop placement: uneven widths, alignment at visually meaningful positions, etc.
    • Spaces can never do this — they’re locked to fixed increments. Tabs are strictly more expressive.
  3. Tabs give readers control.
    • Each developer chooses their own preferred view without touching the file.
    • Spaces strip away that freedom and impose one person’s taste on everyone.
  4. All-spaces style guides confuse the issue.
    • They’re relics of early tooling quirks. Modern editors and diff tools handle tabs correctly.
    • The persistence of spaces is sociology, not technology.

So the purest position is:

  • Indentation = tabs. (structure)
  • Alignment = optional spaces. (presentation, but outside indentation columns)

“A tab isn’t ‘4 spaces.’ A tab is indentation. That’s why it exists. Encoding indentation with spaces is like writing numbers in Roman numerals: it works, but it’s clumsy, inflexible, and obsolete.”

Tomorrow, I will ask it to decide between vi and emacs.