Yes. A law could be a secret law if it was not created in a public way but was still acted upon by the authorities as if it were any other law.
It's an easy concept.
If you don't think we have secret laws then that's a debate we can have, but please don't pretend not to understand the idea. We have secret courts. We have people unable to know the charges or evidence against them. We have press gags on reporting what some court cases are about (let alone the evidence or the defendents' identities), we have press gags on even reporting that some cases exist! We have security services operating beyond any democratic legal mandate based on political 'guidance'. These effectively make up a secret and hidden system of law.
It's an easy concept.
If you don't think we have secret laws then that's a debate we can have, but please don't pretend not to understand the idea. We have secret courts. We have people unable to know the charges or evidence against them. We have press gags on reporting what some court cases are about (let alone the evidence or the defendents' identities), we have press gags on even reporting that some cases exist! We have security services operating beyond any democratic legal mandate based on political 'guidance'. These effectively make up a secret and hidden system of law.
You obviously need to read more Kafka.