What is the defining difference between computer security and information security?  Why can we argue that information security is really an application of social science?

I believe the main difference between computer security and information security is a matter of what is being protected. Cybersecurity focuses on the technical aspect of data stored in a cloud, on a server, or over a network, etc. Cybersecurity focuses on that aspect and while human behavior could be involved to predict how one might approach reaching this information over technology cybersecurity involves understanding firewalls, code, and IT aspects.

Information security involves human behavior on how one might approach getting into a storage room full of hard drives and destroying them. Overall, it involves how one might get in and how it can be destroyed. Such as, where guards may need to stand or what protections to put in place. For example, badge access and motion sensors.

The main difference is cybersecurity or computer security is all about protecting information online with a lot more skill needed to do such and information security needs to be able to predict human behavior on how one might burn confidential papers. Computer security protects from other computers and technology and information security protects from other people. Therefore, social science needs to be involved to predict and understand human behavior.