It is better to remain silent at the risk of being thought a fool, than to talk and remove all doubt of it.
Nobody likes being criticised but, unfortunately it is a fact of life. To be able to respond to criticism with nobility and detachment is an important life skill, which few people have. If we respond to criticism without careful consideration, it can easily lead to unnecessary suffering.
This hung on my father's office wall about 40 years ago, so I doubt the reference to Switzer. The form, as I remember it was, "It is better to remain silent and be thought a fool, than to speak up and remove all doubt." Of course, some would point out that there's Biblical proverb that is probably the root.