This article concentrates on the necessity for teachers in just one discipline area, namely, science, having philosophical competence and using it to inform their professional life--in their classroom teaching, assessing and institutional engagements--in other words, having a philosophy of science teaching. This group of questions and issues might be labelled "discipline-based" philosophy of education. It is comparable to the position argued 40 years ago by Israel Scheffler. Professional educators need to have some appreciation of the body of knowledge, the history and the methods of investigation into which they are inducting students. This appreciation can only be acquired by history and philosophy of science studies. But further, as professionals, science teachers are constantly engaged with questions that assume certain positions in history and philosophy of science. Recognition of the conjunction of history and philosophy of science and science teaching is not optional for science teachers; the diverse questions and fields that constitute history and philosophy of science and science teaching are simply parts of contemporary national and provincial curriculum; they cannot be avoided by science teachers. So if the in-principle arguments for history and philosophy of science and science teaching fail to convince, the in-practice arguments (teaching the curriculum) cannot be avoided. Teachers of other subjects can see how much of the arguments laid out here are applicable to their circumstances.