Living things use chemistry and/or physic to draw energy and materials from the environment to reproduce their form in separate, essentially identical, examples. Non-living things do not. That seem a clear line / subject boundary to me. Why not to you?
BTW - I´m not "freaked out" Why do you think I am?
No crystals change size, not make new essentially identical copies. Yes, I consider a virus a complex life form which is alive, much like a fetus in the womb is, even thought both do depend upon other lifeforms for part of their lives to make more of their kind.I apologize. I thought I was talking to chinglu. But don't crystals form essentially identical copies? Don't viruses?
No crystals change size, not make new essentially identical copies.
If you mean replicate more of the same latice structure, yes but not new crystal of the same form. E.g. as a NaCl crystal grows more of that structure is added to the outside, not a new cubic crystal.They do make identical crystalline structures of other material; it just happens to be attached.
True, but the new part, individual is not of the same form; however it is alive, and may acquire that same form later.Note, many plants and animals also grow and reproduce in this way on a macroscopic level (having to be broken off to create a completely distinct individual).
Prions do convert the same ALREADY EXISTING chemical compound into their form by refolding the pre-existing identical compound. They do not create new life, but only change the shape of existing molecules. They certainly do not draw any material in to make new life from it and take insignificant energy from the environment to do the refolding - possibly all is supplied by molecule they refold if any is required. I suspect they serve just as a template for it to refold with. It is close call, but I would say they are not alive. My definition of living had the living creature make compounds found in themselves from environmental materials and energy, not just change the shape of existing compounds. An oil companies "cracking unit" producing higher percent of gasoline does that, and it is not alive either. Some prions can kill you as the shape of molecule is very important to many cells - many entirely different molecules but with the same shape can trick their shape specific sites - how artificial sweetners and many drugs work.There are also things that are smaller and simpler than viruses- like prions- which happily replicate by using (/bumping into) the raw material around them- that raw material just happens to be another protein (very specific requirements).
Living things use chemistry and/or physic to draw energy and materials from the environment to reproduce their form in separate, essentially identical, examples. Non-living things do not. That seem a clear line / subject boundary to me. Why not to you?
I agree that there is no clear line between living and non living chemical processes with many definitions of life various people have offered. That is why I used some care to make my definition (which you quoted). With it there is a clear line between between living and non-living.... There is an unbroken continuum between simple chemistry and complex life, ... where you draw the line between chemistry and life is an entirely arbitrary decision based on what your definition of life is. ...
I think so*, but all may not yet be known. I.e. I do not believe, as once many if not most did, that there is some special "life force" - I forget its Latin name.The life form as a whole may have unique qualities, but if we consider just a small part of it, isn't it just chemical? Are all the parts of a living thing reducible to chemical interactions?
CERTAINLY I am being arbitrary*, but I realized that. - I was trying to show defend my statement in post 94, that ToE was (or could be) a clearly defined separate domain of study, "cut at a natural joint" from the origin of life. If you cannot do that clean cut of living from non-living mater, then Chinglu has quite a strong argument in his post 93 that ToE, as normally limited to not include abiogenesis, is just religion, not science. I.e. he said in 93´s main summary argument line that:Hi Billy, ... I feel that you are drawing an arbitrary line and rationalizing it without realizing. ...
I was trying to show defend my statement in post 94, that ToE was (or could be) a clearly defined separate domain of study, "cut at a natural joint" from the origin of life.
If you cannot do that clean cut of living from non-living mater, then Chinglu has quite a strong argument in his post 93 that ToE, as normally limited to not include abiogenesis, is just religion, not science. I.e. he said in 93´s main summary argument line that:
"Either TOE is based on the natural operations of chemistry and physics or it is not. If it is, then abiogenesis is part of TOE."
* All definitions are (and not just definitions of life).
I took a second approach in post 94 too, i.e. accept Chinglu´s logic and then note it implied the origin of planet Earth from a gas cloud must be part of ToE too.
Certainly the different domains of science share some common characteristic, for example testing predictions of their theories etc. but also there can be little in common of between some of their subject maters - say between nuclear physics and thermodynamics, etc. To have a well defined subject area for ToE, it is IMHO necessary that definable boundaries of that field exist. As ToE is the study of how life forms change it is thus necessary to know what is a life form and what is not if ToE is to be a well defined field of study.No domain of science can be clearly or perfectly separated from another- they merely are in practice of those fields of study due to specialization. ...
Certainly the different domains of science share some common characteristic, for example testing predictions of their theories etc. but also there can be little in common of between some of their subject maters - say between nuclear physics and thermodynamics, etc.
To have a well defined subject area for ToE, it is IMHO necessary that definable boundaries of that field exist. As ToE is the study of how life forms change it is thus necessary to know what is a life form and what is not if ToE is to be a well defined field of study.
Unlike history, science does have natural, non-arbitrary, boundaries for its fields of study.
I have discussed prions and viruses already and with my definition a virus is alive and a prion is not
If you cannot do that clean cut of living from non-living mater, then Chinglu has quite a strong argument in his post 93 that ToE, as normally limited to not include abiogenesis, is just religion, not science.
Definitions are arbitrary. Mine for life, requires that the life form takes energy and material from the environment to reproduce, which prions do not. Some existing protein molecules can be refolded during collisions to make the "hit molecule" into the prion version that molecule even if the molecule or atom that hit the "existing protein molecule" is not a prion, or not even the shape of the prion. There is a whole field of study of many so called "chaperons molecules" that control the refolding of proteins.* Thus when it happens to be a prion that hits the existing protein molecule to trigger the refolding making another prion, I don´t consider that refolded molecule to be life. It could have been created by non-piron collisions too - no "reproduction."Billy T Then you have a problem with your definition, as prions are clearly on the living side of the divide ...Prions create copies of themselves from elements in their environment, they reproduce. ...
Definitions are arbitrary
Yes, but with care, as I took, in making mine, it is possible to draw the line between living and non-living clearly.Billy T And thus the demarcation between life and non-life is also arbitrary. Grumpy