Nonono, you just use non-subjective observations like well-constructed statistics.
Torture numbers, and they'll confess to anything. ~Gregg Easterbrook
98% of all statistics are made up. ~Author Unknown
Statistics are like bikinis. What they reveal is suggestive, but what they conceal is vital. ~Aaron Levenstein
Say you were standing with one foot in the oven and one foot in an ice bucket. According to the percentage people, you should be perfectly comfortable. ~Bobby Bragan, 1963
Statistics can be made to prove anything - even the truth. ~Author Unknown
Facts are stubborn things, but statistics are more pliable. ~Author Unknown
He uses statistics as a drunken man uses lampposts - for support rather than for illumination. ~Andrew Lang
Statistics are like women; mirrors of purest virtue and truth, or like whores to use as one pleases. ~Theodor Billroth
Do not put your faith in what statistics say until you have carefully considered what they do not say. ~William W. Watt
Then there is the man who drowned crossing a stream with an average depth of six inches. ~W.I.E. Gates
There are two kinds of statistics, the kind you look up and the kind you make up. ~Rex Stout, Death of a Doxy
Satan delights equally in statistics and in quoting scripture.... ~H.G. Wells, The Undying Fire
The average human has one breast and one testicle. ~Des McHale
A statistical analysis, properly conducted, is a delicate dissection of uncertainties, a surgery of suppositions. ~M.J. Moroney
"There are three kinds of lies: lies, damned lies, and statistics." ~Mark Twain
And, in fact, Trashman, personality is about 60-70% genetic, depending on the trait (openness, conscientiousness, extroversion, agreeability, neuroticism.) I can throw you a few papers if you like.
And the moon is made of cheese.