Mostly lawyers.
There are damn few businessmen in Congress or the Senate, at least the kind that actually had to make a profit and meet a payroll.
I understand why you had to try and shoehorn that in there.
There is only one principle or philosophy that matters: "The greatest good for the greatest number." All you have to do is get everyone to agree just what that is.
In the absence of principles, that judgment is generally made by the ones with the most power.