Hundreds of years ago, the famous British Economist Adam Smith first metioned the idea of "social diviation of labor", and because of that, our society can now develop in an unprecedented high speed. However, as different jobs are paid unevenly in the society, some people wondered that whether we should also treat teachers in different fields with different pay schemes.  Some people also believe that a school or college should pay its teachers at the same rate in all disciplines, regardless of differences in salaries for related fields in the world outside of school, they think, for example, entry-level teachers in mathematics and in the arts should receive the same pay, even if outside of school, math specialists earn a much higher salary on average than do specialists in the arts. However, I could not entirely agree with both opinions. I think that the idea of giving different teachers a different pay scheme due to the courses they teach is partly practical, especailly in higher educational institutes like universities and colleges, but in primary and middle schools, I do believe that we should treat each teachers as equals and provide them with the same pay scheme.
It is the current trend that we treat people in different fields differently on their payment. For example, people working in finance sector earn a much higher salary than people in other sectors. Furthermore, teacher is also a kind of occupation, it is justifable for us to provide teachers with different pay scheme according to the course they teach. For instance, teachers in business schools should be paid a higher salary because of the high tuition fees they paid in their schooldays, and large sums of money they paid for job-qualification certificates. It is also reasonable for teachers to reclaim a compensasion for their loss opportunity cost. Many famous business school proffessors have their own company, and they can earn much more money in their own business while they choose to teach  in the universities. Therefore, it is no wonder why some of them charge a large sum as their salaries.
One step further, by introducing pay schemes which differ in different fields can do a lot of good to higher eductional institutions like universities and colleges. For one thing, by providing more money to professors in those fields difficult to develop can a university attract more needed talents to the university. It is not only good for the university or college themselves to further academical researches, but also good for students who study in that school to have a deeper knowledgement of related fields they are studying. The Hong Kong Polytechnic University, PloyU for short, conduct this kind of pay scheme since its foundation in the 1970s. Nowadays, after nearly 40 years of development, the PloyU has become one of the best universities in Asia, and its business school has become the best in Asia. Its alumni, including the 2009 Nobel Prize winner Gao Kun, are enjoying high reputations both in and out of Hong Kong.
Nevertheless, it is not rational for us to provide teachers in all kinds of schools with the different pay scheme. In primary and middle schools, however, as the requirements to become a teacher in those schools are not as strict as those in universities and colleges, it is not good for teachers in lower levlel educational institutions to have different payments due to the courses they teach. There will be also some negative influence due to different payments, because less paid teachers may become less passionate and have a bad influence on children's attitudes towards the course. If those influences children keep the negative thoughts for their entire lives, it is definitely harmful for their development to become a well-developed person. Nowadays in China mainland, science courses teachers are better paid than teachers teaching history and other literal courses. Therefore, many young Chinese are just learning maths, physics, chemistry without even looking at literature, history and so on,and this has done a great harm to those youngsters in their lives.
 It is true that whether all kinds of schools entirely use differed pay schemes are not fair for many teachers. However, not using this kind of scheme just because we want to avoid the disadvantages it brings is not fair, either. I do believe we should put this differed pay scheme in to use, especially in universities and other higher educational institutions, while in primary and middle schools, we should provide teacher with the same pay scheme.