"A definition is a statement of what something is, and what it is not"
(nota: mc2 means mc the power of 2)
Why is e=mc2 a definition?
1. The left hand side says what e is
2. The right-hand side says what e is not.
If you simply interpret (2) as: ALL mc2 is e, (it means like: A dozen is 12 (units), and 12 (units) is a dozen). But dig deeply in the meaning of ALL Energy is mc2. Consider what is the negative form of ALL Energy is mc2? ALL non-Energy is non-mc2. We can put it in non-jargon by saying that ONLY mc2 is e.
Thus, e is defined: ALL energy is mc2 and ONLY mc2 is e (we defined "e" based on the concept: what "e" is and what "e" is not.
Applying to social science PhD research, when defining your PhD topic (you should follow this if your potential external examiners would be the experts from US), the correct way is by referring to the concept mentioned above.
Example 1: Definition of "Economics"
Economics is defined as the production and distribution of goods and services. It means that “ALL Economics is the production and distribution of goods and services” and “ONLY the production and distribution of goods and services is Economics”.
Example 2: Definition of "E-commerce"
In general (looking at the literature), the basic concept of e-commerce focused on two keywords, the process i.e. buying, selling etc. and the medium of transaction i.e. the computer network. When you are defining your research topic at PhD level, the definition of "e-commerce" should be as follows:
“ALL E-commerce is the process of buying, selling and exchanging product, services and information via computer network” and “ONLY the process of buying, selling, exchanging products, services and information via computer network is E-commerce”.
Semua discussions di atas adalah berkaitan dengan "Definition of Topic". Operational definition akan dibincangkan dalam entry seterusnya.
Further readings on this topic could be found in a book "Pre-PhD Proposal Preparation: Problem Formation & Formulation" written by Prof. Emeritus Dr. George K. Chacko (Chacko is a Prof at University of Southern California, LA, and Prof. Chacko dipinjamkan sekejap untuk mengajar kelas PhD di MMU). Bukunya diterbitkan oleh THOMSON Learning dan juga boleh dibeli secara online.