"It is a barren kind of criticism which tells you what a thing is not"

This quote by Alfred Whitney Griswold is a suggestion that criticism ought to be positive and not devastating. It is simple to point out the defects in something, however it is far more challenging to use practical suggestions on how to improve it. Griswold is recommending that criticism should be concentrated on what a thing can be, rather than what it is not. He is motivating people to think favorably and to focus on the potential of a thing, instead of its shortcomings. This type of criticism is most likely to be advantageous and to cause favorable modification. Griswold is emphasizing the importance of providing constructive criticism, instead of merely pointing out what something is not.