Are you saying that Langton's "can be separated from" is different from Rosen's "keep the organization and throw away the matter"? I mean, I think the two have big differences when these comments are seen in total context of their full works. But I am not sure what you are asking/saying...
Dan, John,
Look at the quotes again. Think about the difference between building models of some material system versus the notion that "the ‘logical form’ of an organism can be separated from its material basis of construction". In particular, what does the phrase "can be separated from" mean?
Regards, Tim
Langton’s and other’s view of Artificial Life is that they also want to get beyond particular material realizations of life. Langton says: “Of course, the principle assumption made in Artificial Life is that the ‘logical form’ of an organism can be separated from its material basis of construction, and that ‘aliveness’ will be found to be a property of the former, not of the latter.” (Artificial Life, Langton, ed., Addison-Wesley, 1989, p.11.)