1, bidirectional thinking means that people need positive thinking and reverse thinking about things. First of all, thinking is the generalization and indirect reaction process of the human brain to objective things by means of language. Thinking is based on perception and transcends the boundaries of perception. Thinking in the usual sense involves all cognitive or intellectual activities. It explores and discovers the intrinsic relationship and regularity of things, which is an advanced stage of cognitive process.

2. The indirect reflection of thinking on things means that it understands objective things through other media and infers unknown things with the help of existing knowledge, experience and known conditions. The commonness of thinking lies in its rejection of the non-essential attributes of a class of things and its reflection of the same essential characteristics.