I understand what you're saying, but fairness is a poor word to use for what you're describing. Especially when you use it in contradicting ways. In your first

I understand what you're saying, but fairness is a poor word to use for what you're describing. Especially when you use it in contradicting ways. In your first example equality is "fair and equal." Removing the "equal" as redundant, you end up with equality being fairness. In your second example inequality is fairness. But somehow the second example is not "fairness" according to your article; it is "self interest." I guess my argument is that in any relationship self interest and fairness are the same thing. To long time friends, 0/100 could be considered fair because it's not really 0/100. There's a lot more equity there than the company. Maybe the guy's a great fishing buddy and some tiny venture is worth so little compared to that you'd just as well give it all to your friend so he can spend more time fishing. Also, because your investment with the person is so much more than the size of the venture, the total cost of walking away may be much more than you are currently losing on the venture. Contrastingly you might not know a cofounder at all. Your relationship with him is worth virtually nothing going in. All you've got is the value of the venture. So as the disparity of initial contributions grows, so grows the desire to find a more accurate equity split. Likewise, because the value of the relationship is only the value of the venture, the cost of walking away is much lower so it is easier to reach that point.