It was mentioned earlier that we can go from pain to pleasure, and from crying to laughing, without going through any void between those "extremes", and the conclusion was that the difference is just a matter of degree, not a difference in kind. In the case of laughing and crying, there is a little bit more to it.

 

Laughing and crying are expressions of feelings, and oddly, they are very similar — sometimes it's hard to tell the difference just from the sound or the facial expressions. Why are such fundamentally different emotions manifested in such a similar way?

 

First of all, "expressions" is a misleading word. Laughing and crying are "hardwired" muscular responses — we don't decide to do them, they just happen, and we don't have to be taught how to do them — we already know. And we laugh and cry even when there's no one around to whom we can express our feelings. So laughing and crying are innate responses. We call them "expressions of feelings" because when we see someone laugh or cry, we know how they feel, hence they have "expressed" themselves. But they weren't trying to express themselves — they simply had an uncontrollable muscular response that revealed their feelings.

 

So what triggers these muscular responses? The hypothalamus would seem to be a likely candidate, since laughing and crying surely have a strong emotional content, and the hypothalamus is the primary structure of the limbic system with efferents leading to the brainstem. And the muscles involved in these responses (mainly the lips, voice box, and diaphragm) are controlled by nuclei in the brainstem. But the biology of the difference between laughing and crying hasn't been identified. So we can only proceed with a functional approach.

 

First, let's consider the situations in which laughter occurs. Consider someone listening to a comedian. She thinks that the comedian is saying something serious. Maybe the comedian mentions things that concern her. Then all of a sudden, the whole thing turns out to be a farce. Suddenly she bursts into laughter.

 

Next, let's think about crying. There's something she really cares about, and everything has gone wrong, and all of her efforts have been wasted... she feels impotent in a part of her life in which she has powerful needs, so she cries.

 

Now: why the similarity between the responses?

 

In both cases, there is the realization that there is nothing to be done about the situation. If she realizes that something serious is actually a farce, there is no need for action, and the pent-up tension can be released in laughter. Likewise, if she is frustrated, but realizes that nothing she does will help, there is no need for action, this time because satisfaction is beyond her reach, and again, the pent-up tension can be released, this time by crying. Either way, the response comes when she realizes that there is nothing that can be done.

 

And what kind of response is it? If she has consciously decided not to take any action, the response is arbitrary, and muscles closest to the brain (e.g., facial muscles) get activated.

 

The difference between laughing and crying is a function of our perception of the situation. We laugh when there is nothing we can do, and we don't see a problem with that. But when we cry, it's something that we really care about. It's not OK that there is nothing that we can do, and we don't "let go" as freely, so crying is more labored.

 

And how come we can go directly from laughing to crying, or from crying to laughing?

 

Because our perception of the situation can change — we can go from thinking that it's OK to not OK, or vice versa. Suppose she is crying, and somebody starts telling her jokes. She doesn't stop crying, wait a little while, and then start laughing — she immediately starts laughing. And she can laugh until she cries; the joke was funny, but it's not too cool when her sides feel like they are ready to burst, so her perception of the situation changes, and she switches over to crying.

 

So the common element between laughing and crying is that some sort of concern was brewing, and then she realized that there wasn't anything she could do about it. She laughed if she thought that it was OK, and cried if she thought that it wasn't OK.

 

Then there is the moral issue. While we all want to experience pleasure and avoid pain, and would rather laugh than cry, it doesn't follow that anything funny is healthy — some comedians mock moral standards, and this makes us laugh, but to do so, we have to be convinced that such is OK, and sometimes, it really isn't. Here we just have to remember that laughter is a release of tension, which "feels" good at the time, but the moral standards that created the tension might have been well-founded, and sometimes we have to renew the standards after such a release. If the standards are based on natural law, this will be easy to do — we just have to recall the consequences of not following the standards. If the renewal process clarifies our understanding of the standards, we're actually better off in the end. But if we lose sight of morality because it's more fun to laugh, we'll pay dearly for that mistake. Natural law is inescapable, and ignoring it merely means that we'll suffer consequences that could have been avoided.