Would you like to merge this question into it? MERGE already exists as an alternate of this question.
In casual encounters with the material universe, we rarely feel any difficulty here, since we usually deal with things that are clearly alive, such as a dog or a rattlesnake; or with things that are clearly nonalive, such as a brick or a typewriter.
Nevertheless, the task of defining "life" is both difficult and subtle; something that at once becomes evident if we stop to think. Consider a caterpillar crawling over a rock. The caterpillar is alive, but the rock is not; as you guess at once, since the caterpillar is moving and the rock is not.
Yet what if the caterpillar were crawling over the trunk of a tree? The trunk isn't moving, yet it is as alive as the caterpillar. Or what if a drop of water were trickling down the trunk of the tree? The water in motion would not be alive, but the motionless tree trunk would be.
It would be expecting much of anyone to guess that an oyster were alive if he came across one for the first time with a closed shell. Could a glance at a clump of trees in midwinter, when all are standing leafless, easily distinguish those which are alive and will bear leaves in the spring from those which are dead and will not?
Is it easy to tell a live seed from a dead seed, or either from a grain of sand? For that matter, is it always easy to tell whether a man is merely unconscious or quite dead?
Modern medical advances are making it a matter of importance to decide the moment of actual death, and that is not always easy. Nevertheless, what we call "life" is sufficiently important to warrant an attempt at a definition.
We can begin by listing some of the things that living things can do, and nonliving things cannot do, and see if we end up with a satisfactory distinction for this particular twofold division of the Universe.
A living thing shows the capacity for independent motion against a force. A drop of water trickles downward, but only because gravity is pulling at it; it isn't moving "of its own accord.
Living things that seem to be motionless overall, nevertheless move in part. An oyster may lie attached to its rock all its adult life, but it can open and close its shell. Furthermore, it sucks water into its organs and strains out food, so that there are parts of itself that move constantly.
Plants, too, can move, turning their leaves to the sun, for instance; and there are continuous movements in the substance making it up. A living thing can sense and it can respond adaptively.
That is, it can become aware, somehow, of some alteration in its environment, and will then produce an alteration in itself that will allow it to continue to live as comfortably as possible.Hundreds of Proofs of God’s Existence Formerly: Over Three Hundred Proofs of God’s Existence Originally adapted from a forum on the Internet Infidels.
Begging the Question.
A form of circular reasoning in which a conclusion is derived from premises that presuppose the conclusion. Normally, the point of good reasoning is to start out at one place and end up somewhere new, namely having reached the goal of increasing the . Devil In The Dark () The Horta was an example of Silicon life.; Now we are really sailing off into terra incognito.
"Here be dragons" and all that. But if you have starships, you almost have to have aliens (Isaac Asimov's Foundation trilogy being the most notable exception).The "science" is called Astrobiology, the famous "science in search of a subject".
In the space environment, water is one of the most valuable things in the leslutinsduphoenix.com can split it into oxygen and hydrogen and use it for breathing, propellant, and in fuel cells.
You can drink it or use it to grow plants and algae in your life support system. Questions and Answers About God, Evolution, and the Big Bang --What the Creationists Don't Want You to Know.
Who are you, and what's your agenda? An argument in favor of the existence of aliens Starting with a given.
And That's A Good Thing The Human Aliens trope as happiness is a pursued state of mind used in popular culture When a the reaction of japan and china on imperialism creature from a planet other than Earth looks like a human.