I.e. with engineering, reality is the check on the validity of your critical thinking. With liberal arts, there is no such check.
It's not hard to imagine going to a liberal arts college where the professors are all moderately to aggressively liberal and/or Democrat.
I'm not saying that it's RIGHT that this could happen, but that it's not unreasonable to expect that it COULD happen.
I don't know if that's because internet commenters in general just use the preceding comment as a springboard to jump onto their own soapbox, or if HN users are particularly bad at reading and responding to the content of a text (while loudly denouncing such worthless literary skills).
Is this really a good thing? There are certainly plenty of things in this world that are relative, unanswerable, or heuristics based on differing utility functions. But arguments about those things should still be logically right, based on differing assumptions that are made explicit.
Even then, there's the foggy feeling that remains, every thought exists in some context with some assumptions. You can continue to question what assumptions exist that you aren't aware of, and redefine your opinions through that vocabulary instead, and perhaps convince yourself into a point of view you would never consciously switch to given knowledge of the prior, through the trickery of time and language.
Trying to maintain a coherent view of the world assuming the possibility of relativism across all domains is insanity. Trying to function with that mass of unanswerables leading to possibly infinitely descending chains of undefined, fuzzy variables is like hitting a wall of meaningless symbols. It makes doing things in reality trivial. The task of coming to know what you explicitly, continuously define as unknowable is impossible.
In theory, logic is beautiful. But there's stuff that makes logic seem incomplete, when it comes to application. At the trail end of the thought, it still feels like thinking about everything all at once, while knowing nothing.
The entire world isn't engineering, and there are plenty of things that we have to agree to disagree on (we can come up with objective solutions that minimize the disagreement, but that only goes so far). Since softer subjects will always lack clear objective answers, we could hope for a change in liberal arts teaching that required creating independent rational arguments rather than getting by by restating the specific one the professor happens to believe in.
As opposed to, say, arguing about who is a better President - Obama or Bush? Liberal arts majors can argue that all day, and never be able to demonstrate a thing to be true.
Note that there have been many scientific theories that were debated persuasively, reasonably, and logically, until someone applied the scientific method and proved one side correct and the other false.
Consider:
http://en.wikipedia.org/wiki/Critical_thinking
It doesn't even mention the scientific method!
http://en.wikipedia.org/wiki/Scientific_method
The revolution in the human condition has been brought about by application of the scientific method - it's the most useful critical thinking skill ever devised.