Just What Is Life?
 

How would one define life? What does it mean to be alive? John Keosian, author of The origin of Life wrote "The origin of life...as an examination of the mechanisms operating in the transition of matter to higher and higher levels of organizations."

So what is life? I was thinking about what the properties of what it means to be living...
To Be Able To Reproduce
To Be Able To Change/Adapt even Mutate
To Be Able to Move, Adjust Position
To Metabolize - respire, injest, digest to sustain or grow, excrete
To Grow and experience a Life Cycle
To Respond to Stimuli
To Maintain, Stabilize Internal Functions

Are there exceptions? I guess it could be said that someone in a coma or life support doesn't fit the criteria, but I guess the whole may not, but various parts may - cells that is.

So what is the criteria for something to be alive?

....To realize that you are not separate from the whole. You are one with the sun, the earth, the air. You don’t have a life. You are life....

To Be Able To Reproduce - fire
To Be Able To Change/Adapt even Mutate - whole universe does this
To Be Able to Move, Adjust Position - robots
To Metabolize - respire, injest, digest to sustain or grow, excrete - fire
To Grow and experience a Life Cycle - circular def'n
To Respond to Stimuli - robots, thermostats even
To Maintain, Stabilize Internal Functions - any feedback loop

life is that short span between death

Wow, that's really profound!

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" the life of man, solitary, poor, nasty, brutish, and short."

— "Chapter XIII.: Of the Natural Condition of Mankind As Concerning Their Felicity, and Misery.", Leviathan
-Thomas Hobbes

listen and PLAY "what is life" all things must pass"-george harrison and YOU WILL BE ENLIGHTENED!

hari krishna.

Life is that which avoids the decay into equilibrium.

--Erwin Shrodinger

Meaningless until you become self aware.

Defining Life

The interesting thing is that, as RWebb points out, the "functional" definitions (that are not based on particular biological features) can be satisfied by software that we can write today. Computer malware reproduces, uses energy, and can be written to adapt and mutate. Maybe you add the requirement that the entity be physical, so now the software has to be part of a machine that can replicate itself, something we can't yet do.

Chemistry that attains a certain level of complexity.

One way of looking at it is to take The Human(on assumption we are the empirical definition), then chip away at every element which can be reproduced in a robot:
The brain functions for storage/interconnection/transmission.
The endocrine functions for maintaining chemical balance.
The lungs and GI functions for in/out transmission and utilizing surrounding materials.
The skeletal/muscular functions for support and movement.

The carbon-based cellular form with DNA master programming I'd guess sets most life apart from non-life here on earth, but there could be other forms.

That is a simple question for me. Life is what you make it. I have respect for others - that is I don't tread on other people's feet and I don't let them tread on mine.:):)

I can't say.
But I try my best to make everything OK.

Dude. what's with all this hypothetical deep stuff lately. You looking for some help with something?

Try to follow the rules, try to do the right things, and all the answers will be clear eventually.
Faith = Strength.

This hypothetical deep stuff enables him to be an authority on all lubey things and hence the published work. I do however give him extra credit for the challenging questions he comes up with. You can't keep a good man down.Yes I agree with you about the help. He has come to the right place. :):)

Its kinda like a box of chocolates......

Life is a cell with a single purpose of replicating its DNA. Rather brilliant actually.

I agree with the exceptions, but what fits the list as a whole. Death must be added to the list I believe.