The Greeks knew it but left the knowledge pasted inside the pages of philosophy. The founding fathers knew it and crafted a system of government based upon a keen insight into man's fallen nature.
The works of William Shakespeare are a goldmine of human nature on display: Love and hate, lust, greed, anger, abuse of power... it's all there.
Justice and Mercy
In The Bard's play, Measure for Measure, Claudio is condemned to die for knocking up his betrothed before the nuptials. In act II, Isabella, Claudio's holy and virginal sister, pleads for mercy to Angelo the magistrate.
Angelo rightly reminds her that True Justice lies not in some sappy sentimentality or misguided empathy. True Justice, God's Justice, Nature's Justice, is blind to emotional appeals and always balances the scales.
Isabella: Yet show some pity.That last line sounds callous, but the deeper meaning is that each of us should be satisfied when justice is done, even when it is done against us, for that is the cosmic order. Adam Smith, who no doubt was familiar with Shakespeare, summed it up succintly:
Angelo: I show it most of all when I show justice;
For then I pity those I do not know,
Which a dismiss'd offense would after gall;
And do him right that, answering one foul wrong, Lives not to act another.
Be satisfied; Your brother dies to-morrow; be content.
"Mercy to the guilty is cruelty to the innocent."
Abuse of Power
Counterpoised against a righteous exercise of justice is abuse of power. Isabella laments how men harshly wield the power lent to them by God:
O, it is excellent to have a giant's strength;Abuse of power is timeless...
but it is tyrannous to use it like a giant.
Could great men thunderShe reminds us that God loans power and authority to man so that we may model our societies upon His justice. But "proud man..."
As Jove himself does, Jove would ne'er be quiet,
For every pelting, petty officer
Would use his heaven for thunder.
Nothing but thunder!
Drest in a little brief authority,So it's not just an abuse of power and authority man engages in, but a usurpation of God's gifts that are loaned to us. We forget we are "dust and to dust we will return." Flush with pride and earthly arrogance, we forget we are fit for eternity, and we end up as angry apes who make the angels weep. Were the angels mere earthly creatures like us, they would spare the pity and simply laugh derisively at us.
Most ignorant of what he 's most assured,
His glassy essence, like an angry ape,
Plays such fantastic tricks before high heaven
As make the angels weep
who, with our spleens,
Would all themselves laugh mortal.
* - Jove: King of the Gods in Roman mythology, god of sky and thunder