G. Ellis was the author of the Scientific American article I had referred and also later co-authored another one in Nature.
But other authoritative people go on debating Ellis views with strong arguments - see :
http://www.space.com/32452-can-science-explain-the-multiverse.html
Which Scientific American article do you refer to?
Anyway, this link at space.com does not give strong arguments against Ellis' views. They basically come up with arguments about 'indirect testing' about which I wrote elsewhere:
"Yet perhaps eventually we will arrive at a theory that is considered the correct fundamental theory of physics – it will account for all observations in cosmology and particle physics, it will be well-tested by experiment, will lead to many correct predictions, and will have a tight structure. The equations of that future theory may imply that the universe has a multiverse structure with each of the domains having physical parameters with different values. One might suggest that this may constitute a ‘theoretical proof’ that the multiverse is correct. However, in order to qualify as science in the usual sense there would still need to be observational proof that the multiverse, which is expressed in these equations as mere potentiality, is in fact actualized (confusing potentialities with actualities is a grave mistake in science). Such an observational proof is not possible.
"All in all, I therefore have to agree with George Ellis that the multiverse hypothesis is not science, but philosophy. It is philosophy dressed up in scientific language. Certainly, it may be called a hypothesis from science, but it hardly qualifies as science proper."
***
Also, in the context of discussing Smolin's hypothesis of Cosmic Natural Selection I wrote about an issue that has bearing on the arguments bought forth in your space.com link as well:
"Smolin nonetheless claims that Cosmic Natural Selection is a true scientific hypothesis since it is falsifiable, i.e. it would fail if some of its predictions do not work out – predictions that are not at all directly related to the workings of the hypothesis, such as upper limits on the mass of neutron stars. However, this is ascribing an exaggerated role to Popperian ideas about science. Yes, falsification of wrong hypotheses and lack of falsification of potentially right ones is an important part of how science progresses, and Popper was certainly right about that, but the main business of science is positive verification by observation and experiment. The theory of evolution and the theory of the Big Bang (not to speak of the atomic theory, quantum theory, general relativity etc.) are such strong scientific theories because they have successfully undergone verification by positive evidence on many levels. How else than because of all the positive lines of verification could Martin Rees come to the reasonable conclusion that he is now 99 % certain – as practically certain as it gets – that the Big Bang happened (book
Just Six Numbers)? And would you seriously suggest that a cancer drug works because there is a lack of falsification that it does not – rather than positive verification that it does?
"Thus, the fact that a hypothesis is falsifiable is not enough to make it scientific. It has to be able to actually be verified, to be
positively tested. I am confident that almost all scientists who like me perform positive testing by observations and experiments will agree."
