I think there obviously needs to be a distinction made between "life" and "something that is conscious". Most agree that there will be life that isn't conscious, at least to a level where it's clearly distinguishable from non-conscious matter. Considering that all life basically came from self-replicating molecules with a capacity to imperfectly replicate occasionally (mutation), the least arbitrary definition of "life" I can think of is just a set of molecules with the capacity to self-replicate. — tom111
I must say that this is the most thoughtful response I have gotten on my thread thus far. I will try my best to give a detailed response because you brought up a lot of very valid points. To start with the 1st sentence of the post. It seems rather tricky to distinguish between what is alive and what is considered conscious. This is because as you have stated later in the post, it’s impossible to show whether or not a particular type of thing is conscious. Rather, when we hypothesize that a being appears conscious, it is due to the observation of the ability of the being to display autonomous behavior and decision-making capabilities. The types of things that we believe to be conscious tend to be the types of beings that display what is sometimes regarded as autonomy. So, perhaps it would be better to distinguish between living things and autonomous things rather than distinguishing between living things and conscious things. While this may be an acceptable path, I think there is a case to be made for bridging the divide between the 2 categories of things of interest to us.
What I think gives us a potential invitation to do this is the double meaning of the word “life”. We tend to use the word scientifically to refer to any organism. But in everyday life, we only treat animals as living and perhaps we shall treat AI as such in the future. For example, imagine that you have a plant in a pot in your house. The plant likely seems like any other object in the house to you. It’s just like a decorative statue that you have to water every once in a while. But imagine that one day, you saw the plant branches moving on their own and suddenly the plant pulls itself out of the pot and starts walking on its roots. It would makes sense to say that the plant had just came to life, even though it was classified as a living thing prior to that event. Of course, I am using 2 different senses of the word “life” here. Nonetheless, I tend to think that if there are 2 distinct definitions of a particular word, then we should either select one understanding of the term over the other or take an either/or approach . The either/or approach would be to define living things as either those things which appear to be alive or those things which replicate themselves and have a metabolism.
I find this approach somewhat problematic though. It seems that many robots could still qualify as life by the scientific definition for relatively arbitrary reasons. Hypothetically, there could be a robot whose only 2 functions are to build other “daughter robots” which share some inherited characteristics with the “mother robot” and to repair itself with materials found in the environment(aka “robot metabolism”). Imagine that they built those daughter robots without appearing alive but rather almost like a boring stationary 3D printer. There could be an eventual evolution of these robots through this process over the course of millions of years. Eventually, these robots might be more complex than humans in their behavior patterns. These robots would appear to fulfill all the requirements for the scientific definition of life except they are not composed of cells. But, this seems like a rather unnecessary requirement. If we were composed of something other than cells, we would probably not make cellular composition one of the requirements for life. But we can also challenge more of the scientific requirements of life. For example, should a self-replicating and self-repairing non-autonomous AI which performs its reproductive and metabolic functions like a plant be considered closer to a living thing than a non-replicating and non-metabolic autonomous AI which behaves like an animal? I tend to think that the latter type of robot appears to be more of a living thing.
As a side note I think there are some interesting ethical implications to your question, if we were truly to come up with a way of determining whether something is alive or not, does that mean certain things will have different levels of 'aliveness' than others? What impact will this have on animal rights? Are they conscious enough so that the killing of them for food is morally wrong? What cutoff point do we set ourselves? Is it only ethically sound to kill something with 0 consciousness or do we set some arbitrary threshold level on the scale of consciousness to decide what's moral to kill and what's not? What about a foetus, is that conscious? What will that mean for abortion law? The possibilities are endless. — tom111
I do think that this question poses some serious ethical implications. But, our current scientific definition of life seems to also be ignored in many of these dilemmas though. When some social conservatives speak of the sanctity of life and the need to protect the lives of fetuses and comatose patients, they are sometimes not being consistent with either of the definitions of life that we are discussing. With the scientific definition of life, some of these social conservatives are being needlessly exclusive with the types of things they categorize as moral patients. They consider fetuses and comatose patients as living things which are sacred yet exclude all the other types of living things which are not human. I simply find this to be unjustly prejudice towards members of your particular group. If such prejudice is justified when it’s not clear why racism is not. Though, as a counterargument, you could perhaps justify the prejudice for fetuses over non-human animals. This is because most fetuses have the potential to become a human being with greater complexity than an animal. Though, it’s hard to see how we would justify spending a millions of dollars of taxpayer money to cover the medical costs of a single comatose patient who has no loved ones and is extremely unlikely to ever be conscious of autonomous especially since we could use that money to improve the welfare of other beings which can likely experience things and have autonomy. If we were to accept my definition of life alongside the belief in the sanctity of life though, then we could exclude both never-conscious humans and plants as moral patience(unless we have some other reason to include them). On the other hand, we might have to include some robots in the future as moral patients. By my definition, only humans and non-human animals can possibly be regarded as moral patients to date. If we reject the sanctity of life beliefs, then we could evaluate moral patience on the basis of other properties. Philosophers like Peter Singer and Shelly Kagan, who reject sanctity of life arguments, generally conceptualize moral patience hierarchies on 2 qualities which I have claimed are indicative of being alive. These 2 qualities are, of course, consciousness and autonomy. I think my definition of life helps bridge together the sanctity of life belief with what is regarded as the most value relevant properties of life by the rejectors of the sanctity of life claims. Of course, I cannot answer whether or not eating meat, abortion, or the mistreatment of future robots is morally permissible without writing you another essay about those topics. I will say that the debate seems to revolve around whether the interests of sufficiently mature humans can override the interests of less complex beings that are believed to have some amount of moral patience. This question is quite complicated.