I'm still catching up on From Wine to Water, but I thought this post was worth commenting on. Ivan argues that, in spite of the obvious fact that two contradictory statements cannot be true, our day-to-day thoughts contradict themselves all the time. As an example, he describes a person who eats meat because it tastes good but also believes that killing animals is morally wrong. I enjoyed reading the post, but I don't think Ivan is correct here for a couple of reasons.
Firstly, the actual contradiction he teases out is not entirely accurate.
...to get an out-and-out contradiction, we need to do a bit more work, and
probably to draw upon other things we believe to be true. For example,
we might believe that 3) we will eat animals since they are delicious,
and 4) we will not do things that are terrible. The explicit
contradiction now emerges: We will not do things that are terrible, such
as hurting animals. And we will hurt animals to eat them, since they
are delicious. We both will and will not do something terrible. P and
What Ivan meant here with point (4) - and, Ivan, please correct me if I'm wrong - sounds more like 4b) we should not do things that are terrible. There's no contradiction between "we will eat meat because it is delicious" and "we shouldn't eat meat because of the cruelty involved".
Another possibility is that Ivan meant 4c) we do not do things that are terrible. This seems closer to the way most people think, since after all it's very hard for anybody to accept that they do terrible things. But there's no necessary contradiction between "we do not do things that are terrible" and "hurting animals to eat them is terrible"! We might imagine a point 5) if we do not eat this meat, somebody else will, or a point 6) eating this meat helps the farmers and abattoir workers feed their own families. Neither of these points are particularly good arguments, but that is not particularly relevant*. To the extent that meat-eaters usually think their meat-eating out, it's highly likely that hey avoid a contradiction by the use of some such rationalization.
Most importantly, though, I want to question Ivan's implicit assumption that most people do think out their practices in this way. Since there's no immediate and obvious contradiction in "hurting animals is wrong, but I still eat meat", the law of non-contradiction does not apply**. In the absence of a serious philosophical inquiry into your own justification for meat-eating, your justification is far too vague to contradict or be contradicted by anything!
Unlike Ivan, I think that people usually do obey the law of non-contradiction in their own thought. You can see this if you argue against, say, somebody who eats meat. If you point out an apparent contradiction, as Ivan did in his post, they will invariably argue against you or come up with an alternate rationalization for eating meat (assuming they don't change their mind). What they will not do is shrug their shoulders and calmly accept the contradiction. Ivan is wrong to argue that human cognition does not obey the law of non-contradiction, but he's not all wrong. Human action, of course, breaks the law of non-contradiction all the time - and that's why we need philosophy.
* Full disclosure: I am a vegetarian who believes that eating meat is ethically wrong.
** If there is an "immediate and obvious" contradiction here, then there is also a similar contradiction in this example: "I wish to go to the post office, which lies due south from my apartment, but in order to get to the door of my apartment I first have to take five steps north."