There are actually two separate issues. First is the question of whether
the above criteria are adequate to recognize life, or whether additional
criteria must be met. The most important potential additional criterion is
transmission of information (DNA, RNA, or some other molecular set of
instructions). If such additional criteria are required (or if the above
criteria are defined more stringently so as to exclude the behavior shown
by the "protocells"), that would constitute a rebuttal. I believe Fox
thought of the information transmission as a later addition.
The second is what is the actual course taken in the formation of life on
earth. It may be possible to create life in the lab by a process rather
different from what actually happened. The current prepondernace of
opinion seems to favor the primary importance of the information
transmission mechanism, although some cellular packaging (similar to what
Fox developed) would be very helpful in protecting and sustaining this
information-carrying molecule.
David Campbell