How do Socialists respond to the Austrian School's "economic calculation problem" criticism?

[D S]

1. Economics is not a science
2. No economic theory (and there are not that many) has every been able to actually reflect reality or have predictive qualities (and I have studied and tried to prove a few statistically and practically)
3. Neither socialism nor capitalism in their pure form have ever existed
4. No economist has ever had to respond to another school's criticism, since there is no theory working in any real time that is measurable, so nobody can disprove the mindless drivel/postulates that economists write.

Humans have found out over the centuries that a combination of co-operation and competition works best and that to organise in groups with similar objectives (pooling of resources) is useful.
Anything beyond that has developed and is changing 'accidentally' into all directions.
So, don't get so uptight about being capitalist, socialist, communist, atheist, believer of the FSM or any other theory. It won't help your long-term survival.