Life
Life is a characteristic that distinguishes physical entities that do have biological processes, such as signaling and self-sustaining processes, from those that do not, either because such functions have ceased, or because they never had such functions and are classified as inanimate. Various forms of life exist, such as plants, animals, fungi, protists, archaea, and bacteria. The criteria can at times be ambiguous and may or may not define viruses, viroids, or potential synthetic life as "living". Biology is the science concerned with the study of life.
Perspective
The perspective on ourselves that we get when we take the point of view of the universe also yields as much objectivity as we need if we are to find a cause that is worthwhile in a way that is independent of our own desires. The most obvious such cause is the reduction of pain and suffering, wherever it is to be found.
Peter Singer, Writings on an Ethical Life (2000), p. 238
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