Cntxt is yr frnd.
Life escaped the rocks when it evolved a cell wall, say Martin and Russell. Controversially, they argue that the two main kingdoms of primitive life, the bacteria and the archaebacteria, have such different cell walls that they must have arisen twice.Others disagree. "It's quite impossible that it could be right," says evolutionary biologist Thomas Cavalier-Smith of the University of Oxford, UK. Bacteria and archaebacteria have got hundreds of genes in common, he says. They share other features, such as the way that they insert proteins into their membranes.
Sounds to me like he disagrees with the idea that bacteria and archaebacteria arose independently, rather than saying that the whole thing is "impossible". No?
Yes, but we are speaking of one hypothesis. I believe it comes as a package, Fool's gold and bugs.