They surely have a different idea but what is relevant is that they have the wrong idea.

The wrong idea about what?

Humans are crafty SOBs.

Is there any doubt that some people really do live better lives than others? Must we accept that mass murderers just have a different idea about what makes a good life? — anonymous66

I think that's an inevitable conclusion.

If man does have a nature, then it seems to have changed over time. What was man's nature 1 million years ago? 200000 years ago? 20000 years ago? Rousseau, Hobbes and Locke suggested that man is a blank slate.

On the other hand:

E. O. Wilson's sociobiology and closely related theory of evolutionary psychology give scientific arguments against the "tabula rasa" hypotheses of Hobbes, Locke, and Rousseau. In his book Consilience: The Unity of Knowledge (1998), Wilson claimed that it was time for a cooperation of all the sciences to explore human nature.

The essence of man is truthfulness.

But truthfulness is a virtue and a virtue is a character trait. Character traits are contingent on habituation. How can an essence be acquired through habituation?

How about those with mental disorders or way out of the ordinary experiences that cannot be reconciled with the rest of the group? These are the isolated ones I guess. Empathy is only gleaned at through sympathy as the pain is not really felt together (no reference) only through analogy.