Sentience more important than Life

Posted by on January 29, 2011 in evolution, Uncategorized | 2 comments

When I was growing up, I used to watch “Star Trek: The Next Generation” with my parents almost every Saturday. The shows that appealed to me most were the ones that dealt with some deep philosophical question, and I would keep thinking about these shows long after the episode was over. My favorite character in the show was Data, because he challenged my thinking about what is human, and what is a person. What is life? These sort of questions grabbed my imagination and have never let go.

Just the other day I saw a rerun of one of those episodes, one that I don’t recall specifically having seen before (I seldom remember the individual episodes as I wasn’t paying attention to that as a child.) This was one where the Enterprise was assisting with the setup of some fancy mining apparatus on some planet or other. A female alien had developed a robot to help with repairs and maintenance on the mining equipment. The robots were capable of learning, and could evaluate the situation and create the proper tool to deal with it in an extremely fast period of time. Data was working with her on the project and observed that one of these robots behaved in a way that he interpreted as being as self-preservation by “breaking” itself to avoid being sent into a dangerous situation and then repairing itself later when the danger was over.

This observation leads Data to start wondering if these robots are self-aware and if they may be considered to be life forms. This is a moral problem for him, since if the robots are life forms they should not be used as mere tools and put into dangerous situations without their consent. He goes to the ship’s doctor and asks her “What is life?” It’s an interesting question since he himself is an artificial life form, and she wonders about why he is asking. I liked the way that she answered. She says that no one has ever really answered the question of exactly what life is and what makes a being alive.

While I was going to the University of Louisville, I developed a strong interest in evolution and I registered to take a class called “Unity of Life” which was a class for biology majors on that topic. Since I had a full-time load of 12 hours for the semester, I could take on additional classes at no extra charge. (Unfortunately since I was starting to take difficult upper-level CIS classes, I had to drop my biology course for lack of time.) I did attend the first class though, and I recall clearly the opening discussion for the class. The professor opened the class by asking “What is life?” As it turns out, “life” is not nearly as easy a concept to define as you would assume. In grade school I learned that is something is alive, it means that it grows, metabolizes, reproduces, and passes hereditary material to its offspring. The reason a rock is not considered alive is because it does none of these things. But what about a virus, which is little more than some hereditary material, a protein shell, and a means of transmitting that hereditary material to a host cell? Is that alive?

We have developed our definitions of life by observing things that we consider to be living and describing what they have in common. But that is not a definition, any more than trying to define gravity as that which pulls objects to the ground. That is describing the effect of gravity, but it doesn’t tell us anything about what it is or what causes it. According to the understanding of modern biology, there is not a clear defining line between life and non-life. Look at our own bodies: we are live, our cells are alive, and I suppose the organelles inside the cells are alive. But these things are all made of atoms and molecules, and how could an atom of carbon or oxygen be said to be alive? All living things are made of non-living things. We evolved from the non-living, and we are still made of non-living material. Life is a manifestation of a particular organization of non-living things. When that organization breaks down, we die.

Data was concerned about the definition of life, and whether or not the robots designed to repair the mine were alive. I think he was asking the wrong question. The things that should be considered when determining if a thing should be considered morally is its capacity for sentience. Plants are biologically alive, but very few people would argue against killing them for food or other uses for that reason. What makes a person, a being to be considered morally before we use or kill it, is an ability to think, suffer or feel pleasure. Those are the things that matter.


  1. Very well written. I wanted it to go further. Perhaps a few paragraphs to define sentience. I enjoyed the read but did not want it to end.

    • Thanks Harvey. I may make sentience the topic of my next post. I do agree that there is more to be said about it.