Dissolving the Question of Life

So, dissolve "life." Why do we care if something is alive? To decide if its life has value.

I don't think that's the only reason we care. There's a lot of mostly-true generalizations that we can make about living things -- they require energy to keep living, they have some means of internal self-repair, etc. If I ask whether a vaccine has live or dead bacteria, it isn't because I value the live bacteria more, it's because it lets me assess risks more accurately.

People routinely value non-living things over living things. For instance, many people wear fur. (Or for that matter, cotton.)

What we value is sentience.

This isn't really true either. We have lots of different values. For instance, many people are willing to kill mice to feed their pet snakes. I don't think they'd be dissuaded if it turns out that mice are "more sentient" than snakes by some metric -- they like their [distinctive] pet more than they like the mice, which from their point of view are[interchangeable and replaceable.

We also value rarity -- consider a rare lizard versus a common bird-of-prey.

And we value several kinds of instrumental utility -- foxes might be smarter than chickens, but just ask a farmer which they value more.

tl;dr: Neither life or sentience are strongly correlated with how much most people value something.

tl;dr: Life is an ambiguous term, use sentience to describe a being's value.

Do you suggest that sentience is a less ambiguous term?

I think it's not that hard to make a definition of life that includes everything most people consider alive and excludes everything else. You could just call life anything that stores instructions for making more copies of itself on nucleic acids. Maybe I'm being too glib, I dunno. But the better definitions of life don't really seem to be trying to determine whether edge cases should count as alive or not, which as you note is not really a pressing question.

It's more a matter of saying, "This thing we call life is interesting. What are the characteristics that make it so interesting?" and coming up with things like self-replication, homeostasis, metabolism, that stuff.

There exists a particular cluster in thingspace which we call "living things" and we have invented a magical quality called "life" to apply to members of this cluster.

Virii are peripheral members of the cluster, just like penguins are atypical birds, so there's confusion. There's also general confusion about which dimensions should be considered important, i.e. complexity, intelligence, etc.

Discussions of the meaning of life are confused for the same reason as discussions about the morality of coffee tables.

He offered two definitions; that life acts in a manner to achieve a goal, and that life continuously decreases internal entropy.

Every control system does these things. It acts in a manner to achieve a goal (keeping a perception close to a reference value), and if successful, that implies that the entropy of the thing it is controlling decreases.

That does not make all control systems living things.

So, dissolve "life."

Done long ago. Vitalism is dead.

It's not obvious to me why "every machine that has a function" shouldn't count as alive for these purposes. If someone suggested those definitions in the first place then presumably he's looking for somehting broader conceptually than the carbon based replication we usually mean. (didn't actually watch the video)

Tangential, but the term "sentience" should really be deprecated. It seems to serve no purpose save for enabling conflation between consciousness and intelligence.

I'm not sure everyone spends much time thinking about sentience. But people seem prone to empathy and the more an animal seems like a person, the more empathy we have.

An animal could be more "personlike" on different dimensions including sentience, but also including facial expressions.

Biologists have looked into this. E.g.: J. Maynard Smith and Eors Szathmary - in "The Origins of Life", p.3:

What is life? [...]

An alternative is to define as living any population of entities posessing those properties that are needed if the population is to evolve by natural selection.

Life is the ultimate form of entropy. If you define heat by how much an object increases the long-term unpredictability of the system into which the object is injected, then pound for pound, there is nothing hotter than an RNA molecule which is brought to a barren but habitable planet.