理论是科学发展的关键

 理论思维是科学发展的关键。造纸术、指南针、火药、印刷术是中国古代四大发明，但从唐代到清代却无多少相关理论研究。列举了现代化学中一些精辟的理论例证，说明了理论的重要性。

Theoretics are keys to the science

Theoretical thinking is the key question for science development. Compass and gunpowder belong to the four great inventions of ancient China, but from Tang dynasty to Qing dynasty, no any theoretical questions on compass and gunpowder were ever studied. This article lists a few incisive theoretical examples in modern chemistry to illustrate the very importance of theoretical questions. Perceptual knowledge needs to rise to rational knowledge that must be completely consistent with experimental facts. Any correct theory should grasp the essence of things. From philosophical opinion, practice is the first; however, theoretics have important instructive effects on new and follow-up practices. Therefore, the tree of rational theory is ever green.