The wisdom of repugnance or appeal to disgust, also known informally as the yuck factor, is the belief that an intuitive negative response to some thing, idea, or practice should be interpreted as evidence for the intrinsically harmful or evil character of that thing. Furthermore, it refers to the notion that wisdom may manifest itself in feelings of disgust towards anything which lacks goodness or wisdom, though the feelings or the reasoning of such 'wisdom' may not be immediately explicable through reason.