Readability to me is about clarity, not aesthetics.

How easily can people understand what this code does and how?

This is at least conceptually objectively measurable, though I don't know of any actual attempts to do so.

That's important. But why I say relative - is because the structure and language of readability is dependent on the code culture one is working within, not an outside measure.

That's why things like C coding style is so variable - sometimes within the same body of code (see net-snmp ....)

I'd rather have consistent coding standards but I daily deal with different team projects with different conventions, so I'm used to adapting my own reading conventions as I switch contexts.

Keep a common aesthetic within a project. It's worth it - by measure of success of a project.

This might be bad for maintaining a lively argument in this thread, but I fully agree with that.