NARS (Non-Axiomatic Reasoning System) is an intelligent reasoning system. It can answer questions according to the knowledge originally provided by its user. What makes it different from conventional reasoning systems is its ability to learn from its experience and to work with insufficient knowledge and resources. The NARS 4.1 demo is a Java applet. It comes with help information and simple examples to show how the system does deduction, induction, abduction, analogy, belief revision, membership evaluation, relational inference, backward inference, new concept formation, and so on, in a unified manner. The demo also allows the user to create new examples to test the system, as well as to see the internal structure and process when the system is running. The on-line help information contains links to relevant publications.