Matt never spelt out what the "spirit of socialism" was. That means we are left to discuss nothing. His “argument” is unassailable, because there’s no argument.
Eduard Bernstein was more forthcoming. Although he didn’t use that phrase himself, he defiantly put his attitude towards socialism this way:
“I frankly admit that I have extraordinarily little feeling for, or interest in, what is usually termed ‘the final goal of socialism’. This goal, whatever it may be, is nothing to me, the movement is everything.” (p. xxviii)Again he repeated that, almost verbatim, ten years later in the Preface to the English edition (Evolutionary Socialism).