An engineer, a mathematician, and a physicist are riding a train through Scotland.

The engineer looks out the window, sees a black sheep, and exclaims, "Hey! They've got black sheep in Scotland!"

The mathematician looks out the window and corrects the engineer, "Strictly speaking, all we know is that there's at least one black sheep in Scotland."

The physicist looks out the window and corrects the mathematician, "On one side."

The idea that authorship is a tangible thing has been around for at least 1500 years. The concept that the right to control copying is also a tangible thing came somewhat later when technology intervened to make large-scale duplication at little cost somewhat accessible to the masses - but even that was over 500 years ago with Gutenberg.

To the Internet generation this somehow seems newly quaint. A book can be copied in a click, and carried in essentially no physical space, so does that change the rules?

It can't, because ease of copying and carrying wasn't the principle in the first place. The principle is that the author and publisher are in control of their works. If we're willing to take that away based on convenience, because the publisher or the author hasn't done what we wanted them to do, that's no different from downloading a current best seller or an expensive limited edition.

As to what I'd do given my own morals and ethics: if I'm going to violate the principle, I'm not going to rationalize it to anyone else because I'm not going to TELL anyone else.