Okay, it was really bad humor, but I tried!
A few months ago a dear friend and I were eating salad courses next to each other. She mentioned that she was taught never to cut through lettuce/salad with a knife. As I cut my salad with both knife and salad fork, I recalled having heard that while I was in college. However, I was taught this was an old custom, no longer applicable.
There are two schools of thought on why we were taught not to cut our salad with a knife. I was taught that the acid (vinegar, citrus, tomato, etc.) in the salad dressing would harm/corrode the silver plated or carbon steel knife blades. However, another view is that the acid in the salad dressing would have a reaction to the metal of the knife blades, thus changing the flavor of the salad. In addition, the cut leaf edges would brown more quickly.
Since today most knife blades are made of stainless steel, there is less concern about using a knife to cut your salad, if you choose. The practice of not cutting your salad with a knife had nothing to do with etiquette, good manners or social graces. Rather, it was a practical necessity of good housekeeping.
Scientifically, tearing or cutting lettuce will not make a difference to the cut edges of the leaves browning.
What you do need to know about eating a salad gracefully is to use the appropriate fork and cut it properly. A small, salad fork should be used for a salad course, and a larger, dinner fork should be used for a salad served as an entree. If a salad is served on your dinner plate with other servings (i.e., meat, veggies, starch), then it should be eaten with your dinner fork. When eating your salad, only cut one bite at a time rather than cutting and mixing the entire thing at one time. I get really excited when I see a chopped salad on a restaurant menu. It makes eating the salad much easier.
As a hostess, I always like to serve a well mixed and cut salad to my guests. Again, it will make it easier for them to eat and enjoy.
To recap, go ahead and enjoy your salad with a fork or a fork and knife, either are correct. Cut only one bite at a time and consume it before cutting the next. And choose the appropriate fork. All of the above will keep you on salad footing! 😀
Bonus Information: Did you know that the French do not cut their salad/lettuce leaves, but rather fold them? Using their knives and forks, lettuce is folded into a manageable size and placed in their mouth. I am not sure I am that adept at using my silverware!