Final answer:
The EVERLASTING YEA in Carlyle's works is the acceptance of faith and truth in life, opposing doubt and despair, as highlighted in 'Sartor Resartus'.
Step-by-step explanation:
Carlyle's EVERLASTING YEA may be defined as the affirmation of the possibility of genuine faith, character, and the rejection of doubt and despair. It represents an embrace of a positive, truthful, and meaningful existence against negativities like materialism and skepticism. This idea is prominently featured in Thomas Carlyle's work Sartor Resartus, where the concept symbolizes the author's call to readers to acknowledge a deeper, more spiritual and authentic way of living.