I like Diogenes’ quote, though William Congreave would disagree, he said: “I always take blushing either for a sign of guilt or of ill breeding.” Rousseau was of the opinion that blushing was a sign of guilt. Yet shame can bring the same result, even anger, and so too, a compliment. Blushing communicates sensitivity, humility and a connectedness to self and others. And I think Congreave was a cynic.
My own view is that blushing is an inward feeling made visible, that perhaps we feel naked, transparent, awkward, surprised, and to blush is a response. That warm glow on our face and neck. Maybe if we don’t blush we have become accustomed to these things, and they no longer affect us. But if we don’t feel these things then we die a little. Rabbi Abraham Joshua Heschel said: “An individual dies when they cease to be surprised …” And Diogenes is trying to say that blushing is a good thing, it shows that we are still connected to our feelings, our senses, our understanding of the world and that we have a deep understanding of self and others.
But perhaps you’re more with Rousseau, that blushing is merely showing guilt, but I would only agree on the grounds that I am indeed guilty of being surprised, or feel transparent, naked, humbled, angry, but not necessarily because I am hiding something other than my inner self. Blushing is a sign, a sign of many things that might be happening within me. I think blushing is a mindful virtue rather than just a moral virtue, it is a sign that we also feel and if we let it, it can inform us, guide us, and teach us.