If a lion eats a gazelle , it has a need to survive , and few other vectors for survival . A lion eating a gazelle is not murder . If the lion goes around killing gazelles because it thinks it ' s fun , that would be unjust . Neither the lion nor the gazelles has concepts such as murder and unjust . This isn ' t some fairy tale children book , both animals did what they need to do to survive without any moral baggage . Animals acknowledge property rights by defense . For example , Hyenas will not allow others from different packs in to their area . No , hyena has no clue whatsoever about property rights . Everything it does pertains to only one thing , survival of the fittest . Other animals instead of becoming territorial , choose symbiotic relationship instead , not because they ' re communists but all for the sake of surviving . There are other vectors for survival which don ' t require violating other ' s need for selfpreservation . I didn ' t suggest selfpreservation is the final meaning of justice . The natural world is amoral , without morality , there ' s no violation nor justice and injustice . I suggested it was something justice could be measured against , proving it ' s not arbitrary . I don ' t like suggestive and thus arbitrary stuff , I like objective stuff . Fine . Be we don ' t say dogs do not exist because we can ' t find a perfect dog . Dogs aren ' t mathematics . A perfect dog is relative , a perfect square is absolute . How can we even discuss concepts like morality and justice if they don ' t have essential properties ? We made up those essential properties . The question is , why should others accept your made up concepts ? You must provide a compelling reason why others should accept your made up concepts and they would likely accept if your made up concepts are beneficial to them .