 Also, it is difficult to reason objectively about the question, because a denial that an animal is conscious is often taken to imply that it does not feel, its life has no value, and that harming it is not morally wrong.The 17th-century French philosopher René Descartes, for example, has sometimes been blamed for mistreatment of animals because he argued that only humans are conscious.Philosophers who consider subjective experience the essence of consciousness also generally believe, as a correlate, that the existence and nature of animal consciousness can never rigorously be known.