Note my added emphasis to Luxembourg, of whom I've always thought highly:
You said: Jacob, such ethical socialism is the central theme of misty pre Marxian revolutionary thought. Marxian socialism has an objective foundation. As Rosa Luxemburg put it:
"According to Marx, the rebellion of the workers, the class struggle, is only the ideological reflection of the objective historical **necessity** of socialism, resulting from the objective **impossibility** of capitalism at a certain stage. Of course, that does not mean (it still seems necessary to point out those basics of Marxism to the 'experts') that the historical process has to be, or even could be, exhausted to the very limit of this historical impossibility. Long before this, the objective tendency of capitalist development in this direction is sufficient to produce such a social and political sharpening of contradictions in society that they **must terminate.** But these social and political contradictions are essentially only a product of the economic indefensibility of capitalism. The situation continues to **sharpen** as this becomes increasinly obvious. . . .
And particularly:
"If we assume with the 'experts' the economic infinity of capital accumulation, then the vital foundation on which socialism rests will disappear. . . . "
Infinity is a pretty long time, but the indeterminateness of capitalism's life span should be pretty obvious. In other words, if you can't tell me when it will end, and if it doesn't look like it will end any time soon, its longevity is indeterminate. This would seem to throw quite a monkey wrench into this particular interpretation of Marx.
RL continues: "We take refuge in the mist of pre Marxist systems and the schools which attempted to deduce socialism solely on the basis of the injustice and evil of today's world and revolutionary determination of the working classes." In The Accumulation of Capital--An Anti Critique. MR Press, 1972, p.76
Given the historical evitability, so to speak, of capitalism in the sense I noted above, it would seem that it is precisely in this "mist" somewhere that the case for socialism lies.
Another way of saying this is that we will get socialism when people want it, not when they feel forced to choose it.
mbs