TED Conversations

This conversation is closed.

Life, but not as we know it. Does this statement make sense?

How do we define life? The diversity of life on Earth is so vast and mind-boggling it would be difficult to pin life down to colour, shape, or size.

We can only define life by the biologist definition which says life is anything that performs the 7 life processes which are movement, nutrition, respiration, irritability, excretion, growth and reproduction.

If an object was found outside the Earth that met the criteria for life it would definitely be classified as life. If another object was found that resembled life on Earth (though difficult to say how life on Earth looks like ) but did not meet the criteria would it be classified as life or would the definition of life be bent to include it.

If so why is a similar situation not considered for celestial bodies that meet the definition partially. And also for man-made objects such as cars which are 80% a life form. After-all there is no part of the definition that narrows it to natural objects only.



Showing single comment thread. View the full conversation.

  • thumb
    Jun 26 2013: Definitions can be problematical. If you insist that life as we know it is strictly as defined by the 7-point system then anything which does not comply is not life, by definition. Therefore the answer to your question is, "No. The statement makes no sense." Anyone who has been kicked by a mule will testify that the kick came from a living creature, yet the mule fails to meet the definition because all male mules are sterile. If you allow a different definition which includes life forms not yet discovered, then the statement would make sense.
    • Jun 27 2013: Life is defined for a specie not an individual or group of individuals. If all the members of a human tribe are sterile it does not make reproduction no longer a life process. And even for multi-icellular organisms we look at it from a cellular point of view, the cells of a mule perform all the 7 life processes, yes, its cell reproduce.
      • thumb
        Jun 27 2013: The last of the seven processes you mention as signs of life is "reproduction". Are you asserting that the process in view there is cellular reproduction within a member of a species and not the ability to generate offspring? Please clarify that rather startling assertion. Thank you!

Showing single comment thread. View the full conversation.