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theory; reason; logic
(unreasonable) argument; strained logic; excuse; pretext
彼の言う理窟は筋が通っているが実現は難しい。
His reasoning is logical, but implementation is difficult.
理窟ばかり言って行動に移さない人は信用されない。
People who only theorize without taking action are not trusted.
子供に理窟で説得しようとしても効果は薄い。
Trying to persuade children with logic alone has little effect.