Back in the era relying on physical perception only

the internal changes of the body can only be perceived by inference through external observation and analysis of the cause through the effects

and expressed with metaphorical cognition. The etiology and pathogenesis theory of traditional Chinese medicine(TCM) is the product of such cognitive approach. This paper explored the origins of the theory that came from clinical practices and that cannot be perceived physically

with etiology and pathogenesis of TCM as the main line

and

taiyang

wind-stroke pattern and

Guizhi

Decoction (Cinnamon Twig Decoction

GZT) in

Shanghan Lun

(

On Cold Damage

) as an example.Metaphorical cognition is used to analyze taiyang wind-stroke pattern and GZT

including how cold damage was stated and what was the difference between the language used for the statement and the daily language used at that time; Why GZT has the effect of releasing the muscle and regulating the nutritive and defensive level; Why the etiology and pathogenesis theory works well

and what are the new findings from the etiology and pathogenesis theory. At last

it reveals the differences between the logical determination of propositions and the fact test

with the logical determination of the truth and falsity of conditional propositions and the verifiability of the etiology in TCM.