Don't tell me what for or for what, just tell me what I should do!" It is an urgent demand that we always heard in our labs. However, the results end up being far from satisfaction when postgraduate do experiments strictly by their adviser's guidance. There are many students who are completely indifferent to the theoretical hypothesis and concluding analysis of their research; even if they have read a lot of literature and repeated a lot of experiments in their daily routine. When we ask about

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... heoretical foundations of their research, they are at a loss and can't answer at all. Though there are many reasons for these disappointments, the most important one is because we are used to accepting or following tradition-what other people did-and rarely attempt to explore what other people have never done before. Confucius said: "Learning without thinking leads to confusion; thinking without learning ends in danger". Speculation is a vital part of doing research, like psychologist Richang Cao (Jih-chang Tsao, 曹日昌), a pioneer advocate for applied dialectical materialism to psychological research, reviews his work and methodology which is still worth learning and using today (Zhang, 2006) (Fig. 1) . Prof. Cao is one of the main founders of the construction and development of psychological science after the founding of new China. He advocated that psychology should be used to study the universal law of psychological phenomena, depending on social practice, while guided by the epistemology of Marxism. He explained the development of psychological phenomena and psychology with three universal principles which are the law of unity of opposites, the law of qualitative and quantitative mutual change, and the law of negation of negation. These laws play an extremely important role in the development of psychology in China. In 1943, Prof. Cao started to use material dialectics to analyze some important questions of psychological testing, and published Several Questions of Principle of Psychological Test. In his article, he analyzed the inadequacies of the existing psychological tests by a few common categories of dialectical relationships including: quality and quantity, parts and whole, surface and essence, and so on. He clearly highlighted limitations of the existing tests, like they did only pay attention to the number of repetitions but didn't care about the quality of the analysis, only pay attention to individual parts but didn't care about the whole system, only pay attention to measurement of appearance but didn't care about the essence of things. Those dialectical analyses provided a solid theoretical basis for the construction of a new psychological test system. Clearly, we must have a correct guiding ideology, focused on understanding and mastering the law of nature in doing research. In 1965, Prof. Cao wrote in a preface of translating foreign books, "If we engaged in psychological research without the correct philosophical thought as theoretical guidance, although sometimes you may get some specific results, but we could not get the right conclusions about the nature of the laws of psychology"; "on the basis of existing research results, the use of dialectical materialism will make the experimental study of psychology to a new level". Because of the conscious use of the dialectical materialism in research practice, Prof. Cao has made outstanding achievements in the field of experimental psychology, especially in learning and memory research. It still has a great impact on the development of memory psychology in current China. From 1945 to 1948, Prof. Cao has been studying psychology at Cambridge University. His project focused on "The Time between Learning and Memory" (Zhao, 2001) . During this time, he published many results on the experimental study and graphics memory recognition research in foreign journals. These results are now used as a model of early experimental study of learning and memory in China. In the early 1960's, his work at Cambridge was used to study the effect of time interval on haptic. In his experiment, he was both the experimenter and subject. It was a very specific and unique design. In 1962, he guided a memory research group. On the one hand, he instructed the staff to study the effects of different sensory channels (visual, tactile and auditory) on memory and to explore the mental mechanism of memorization by Pavlov's theory of advanced neural activity and