Nothing should be considered part of what makes a man truly a man unless it actually belongs to human nature itself. The outcomes of our plans are not requirements for being human. Human nature doesn't promise such things. The final results of our actions have nothing to do with what we are as people. Therefore, the purpose of a human life — the highest good that fulfills that purpose — cannot depend on achieving the outcomes we planned and intended.
Nothing must be thought to belong to a man, which doth not belong unto him as he is a man. These, the event of purposes, are not things required in a man. The nature of man doth not profess any such things. The final ends and consummations of actions are nothing at all to a man's nature. The end therefore of a man, or the _summum bonum_ whereby that end is fulfilled, cannot consist in the consummation of actions purposed and intended.