# Some physicists are trying to create “artificial life” from non-living materials. What criteria would artificial “lifeforms” have to satisfy in order for you to consider them to be “life”? And do you think this goal can be reached?

Self-replicating structures.

Definition of consciousness.

Can life be defined as systems which manage to avoid the second law of thermodynamics?

It is definitely a necessary condition, but probably not sufficient.

A possible counterexample are cellular automata, which generate entropy during their time evolution.

One should make the distinction between life and mind. All the minds that we know happen to be living, but computers are examples of thinking systems that do not live.

There are attempts to put together proteins, DNA, etc., and see if they find self-replication.

We do not know. Is the ability to reproduce enough? Then you can have some type of artificial life in a computer.

What is the definition of life? Perhaps creating artificial intelligence is more interesting.

There are computer programs that already can do some IQ tests and perform tasks better than humans. Where do these fit?

Is associative memory important? This is maybe what gives us intuition. We need to understand better how our brain works and then we can built better computer programs.

We think this question is referring to recent quantum chemistry experiments to make self-assembling molecules, which are not necessarily organic, but which reproduce themselves.

Some suggest this isn't so different as making a self-reproducing program or 3D printer that prints itself, and no more exciting.

Other suggest that it should be life because it's an equilibrium process. If you mix oxygen and hydrogen, water appears and we don't call that life. But if water catalyzed more oxygen and hydrogen to form water, maybe we would.

There's also an ethics question. It's not just semantics. Once we define something as life, we treat it more carefully than a piece of paper. So at what point does the thing count as a live? And at what point does it have rights?

What is the connection to physics? Is all that it takes to make something alive its complexity? What about it's consciousness? Is there a finite number of connections/interactions between particles such that we get a phase transition and something becomes dynamically intelligent? At what length scale does this happen?

In the brain, the number of neurons is very very large... and connectivity is very large. But the amount of connectivity is smaller than the number of neurons. So in the many-neuron limit, the connectivity is of order 1.

Do you need fine tuning to be alive? In other words, perhaps connectivity is necessary but not sufficient.

But intelligence seems to be a continuum. So there is perhaps not a sharp, clear phase trnasition.

The feeling of being conscious, we have that... but it's not clear that we can, even in principle, describe that feeling as a physical process. It's very hard to understand how this arises.

People tried to make Ais in the 70s, but they realized very quickly that it is extremely hard. Nowadays we don't try. We have a much better understanding of what can and cannot be automated. Now we know our limits and we call neural networks “machine learning.”

Is there a quantum-ness in intelligence? Does intelligence or free will somehow exist because of quantum mechanics? Some people say quantum mechanics can have no role in the brain, it's too noisy. But this doesn't seem right. Threre are many biological processes that require quantum mechanics.

We don't have any evidence of free will. It's psychology.

The bell inequalities assume free will because we assume uncorrelated inputs. If all the inputs are correlated, all bets are off.

Distinguish between biological life and intelligent life. For the former one requires that it at least be self-replication, has an ability to react to changes in the environment and takes in energy on its own.

See some examples of adapting to the environment in machine learning algorithms which teach robots to walk.

Could view life simply as a process which preserves (genetic) information

Is the goal of life immortality, or would this be a stage of no further change, like thermodynamic equilibrium, in which life has ceased to be life as we know it.

Set up machines and see whether they start talking about machines; that'll tell you what consciousness is.

Does life magnify smaller-order effects? --> How is life special thermodynamically?

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