When you speak with a Scientist about the glass being half-full and half-empty, she/he says that it's a SWAG (Scientific Wild Assumption Guess) based on only visual observation but not substantiated by any experimental data; and therefore it must be inaccurate. She/he will suggest that you do the following: (a) mark the glass at the bottom of the meniscus of the content, (b) pour the content into a bigger glass, (c) fill the empty glass with fresh content up to the mark, (d) add the original content back in, (e) note whether or not the combined content overflows the lip of the glass, (f) conclude that either the glass was more than half full if it overflows, or it was more than half-empty if it doesn't reach the top, (g) conclude that it was either half-full or half-empty only if it neither overflows nor fails to reach the top. Just a word of caution: Don't be surprised if the scientist, doesn't matter she or he, after all that "scientific discussion" asks you: "Now, what was your question again?
Deodatta V. Shenai-Khatkhate