Let's suppose a big ugly monster thingy wants to eat you. While you're running away from it, you're feeling fear. Can this situation be considered one where fear would be rational?
Yes! Of course fear can be rational, especially when there is in fact a big scary monster and you are in danger.
There is an unfortunate meme in society that emotions and rationality are incompatible, but that's not the case. Emotions can only be irrational if you are mistaken to feel those emotions in that context.
Cases where fear is irrational include:
- Fear of cotton balls
- Fear of a non-existent monster
- Not fearing being chased by an actual monster/cheetah/grizzly bear
Now, it's largely up to you to decide what emotions are reasonable for each context, because otherwise the examples become a bit normative. For example, is it irrational to feel a lot of anxiety in social situations? That depends on the social situation, but I'll guess not.
The folks over at Less Wrong have given this sort of thing a lot of consideration. Here's their wiki link to the subject.
The answer depends on your definitions of "fear" and "rational".
If you simplify the complex English semantics, rational might mean either (1) "sensible; not foolish" or (2) "using the faculty of reasoning".
If you understand rational to mean "sensible", then fear can be rational or not, depending on the situation. Fear of mice is probably not very sensible, while fear of heights most probably is.
If you understand rational to refer to cognition (as opposed to affect), then the answer depends on your understanding of fear.
If you define fear as an emotion, then fear can, by definition, not be a cognition. An emotion can be caused by a cognition, it can be thought upon and suppressed by the faculty for rational thought, but it is not a cognition. In this sense fear would not be rational.
How could you define fear to make it meaningful to think of it as not an emotion?
If you define fear as, e.g., an attitude (the attitude of judging something to be dangerous or harmful), then fear would very likely have affective and cognitive components. I am not sure if any speaker of English would accept this definition (even the OED says that fear is an emotion), but you could certainly define fear in such a way -- which would lead to a lot of interesting but unnecessary confusion with your readers.
Psychologists would avoid the word "rational" here, because it is not a scientific term. It is a philosophical term. From this perspective, the opening question is not a question relating to cognitive sciences at all, but to everyday wisdom, and should be closed.
Why are you running away?
1) Are you running because of fear?
2) Are you running because the monster might harm you?
3) Are you running because you've had an encounter with a monster before and even though this one doesn't look like that one and that one had claws and this one doesn't but this one is still coming towards you, kinda fast?
Fear is a marker, like pain. Fear can be automatically activated by occurrences in one's environment in order to activate a response before the conscious mind could possibly have time to react.
LOOK OUT, DUCK! --- Yell this at someone sometime and watch them flinch, down and back. Almost every time.
The problem comes when we aren't paying full attention to our environment, and instead using cognitive shortcuts, such as stereotypes. In these cases, we're using past experiences to inform future expectations - when past experiences are traumatic, we will sometimes (unconsciously) assume negative future expectations, which is the fundamental basis of anxiety.
Is fear rational?
Let me turn that around:
Is a dishwasher rational?
Fear is a tool, baked into the human brain. A dishwasher is a tool. Both can malfunction, both can run improperly (long, short, etc). We can even, over time, reduce our exposure to both (meditation / washing the dishes by hand).
If we run a dishwasher once for each dish we have to wash, that would be irrational. If we feel fear at every occurrence, that would be irrational. If we run the dishwasher without soap, that would be irrational. Unless we have need for it.
It's all about context.