Rational Thought Impossible in Socialist Commonwealth?

Robert pointed out this interesting section in last week's reading:

Without economic calculation there can be no economy . Hence, in a socialist state wherein the pursuit of economic calculation is impossible, there can be--in our sense of the term--no economy whatsoever. In trivial and secondary matters rational conduct might still be possible, but in general it would be impossible to speak of rational production any more. There would be no means of determining what was rational, and hence it is obvious that production could never be directed by economic considerations. What this means is clear enough, apart from its effects on the supply of commodities. Rational conduct would be divorced from the very ground which is its proper domain. Would there, in fact, be any such thing as rational conduct at all, or, indeed, such a thing as rationality and logic in thought itself? Historically, human rationality is a development of economic life. Could it then obtain when divorced therefrom? (pg 14)

He took issue to the last couple sentences as it appears that Mises is saying in a socialist society rational thought and logic would not be possible. I must admit, I am still perplexed by this statement as it does not seem to follow. I understand Mises' point that a pure socialist economy could not happen because of the calculation problem but don't see how this would entail no rational or logical thought. Robinson Crusoe has no "economy" to speak of and engages in no exchanges with other individuals, yet he certainly engages in rational action in choosing means and ends. The primitive tribesmen who are entirely self-sufficient and do not engage in trade and exchange, yet still rationally choose how to apportion their goods to specific ends.

The difference in the socialist commonwealth would be that the individuals are no longer allowed to use producer goods to create products they desire as this will be done by the central planning commission. Because of this, they will not be able to rationally choose which production processes to engage in, but they will still be able to barter the resulting consumer goods (a rational exchange). I'll have to think about this some more, but I am inclined to agree with Robert that this is Mises breaking from economic theory to engage in some personal speculation (which seems inappropriate for a strictly economic essay).

Anyone have any thoughts on this?