Are they, though? The relevant functions in Enum all seem to be zero-based, for example:

    iex> [:foo, :bar, :baz] |> Enum.at(1)
    :bar

Not that it really matters anyway. Like with Erlang, in the vast majority of cases where I'd normally reach for querying a list element by index, pattern matching is the better / more idiomatic option. Compare:

    foo = list |> Enum.at(0)
    bar = list |> Enum.at(1)
    baz = list |> Enum.at(2)
    rem = list |> Enum.slice(3..-1)

with:

    [foo, bar, baz | rem] = list

Both give you the exact same values of foo/bar/baz/rem, but the latter is arguably more readable and concise, and entirely avoids the 0 v. 1 debate.