Maybe this is obvious and not what you are asking, but he's just saying that if you increase your unit of measurement by a factor of X, then the number of such

Maybe this is obvious and not what you are asking, but he's just saying that if you increase your unit of measurement by a factor of X, then the number of such units that comprise your object decreases by the same factor. (Also, this quote is from the Terry Tao blog post that dang links below, not the OP, right?)