There are two practiced points of view along a continuum.
On one end is a philosophy of “All for one and one for all” and on the other end there is the thinking “Every man for himself.”
Which is more rational?
Our ability to determine what is of value would be different given where along the spectrum one falls.
As there is a breadth to the continuum there is breadth to what has value.
At the extreme end of “all for one and one for all” is the thinking that “all” is not just the human species but all life. At the extreme end of “every man for himself” is a disregard for any other life then self.
What about a sense of intrinsic value?
My personal philosophy sides near the extreme end of “all for one and one for all”. That is going to require I value things quite differently then an individual that subscribes to the idea of “every man for himself” where something is of value only if it has potential for exploitation for the individuals personal gain.