The view that I find most logical and close to reality was given by Prof. Dayananda Verma. He says that these lines are formed by our subconscious brain. Whatever our subconscious thinks about us is recorded and these calculations of the brain are sent by electric signals to the whole of our body. They appear as lines in our hands, forehead and feet. In our other body parts, they also make individual differences. You can ask why few people have a certain color of eyes and certain types of nose and so on. As I discussed earlier, the same things that palmistry reveals can also be read from face reading and other branches of Samudrik Shastra; actually many people can do it very accurately even today. Now these calculations made by our subconscious are what our own mind knows about us. Sometimes what our mind says about us in our hand can be different from what we say about ourselves, or we may not want to accept it. The reason is that our subconscious looks at us as a third person unlike the conscious mind that always says I. So our subconscious can reveal negative characteristics such as being rude, cheating, selfishness, fraudulent ways and so on. It shows what it sees about us; in ancient times, people rightly said that hand is the mirror of human character.
This actually explains why hands can accurately tell about past events. Our subconscious brain is a big computer that never forgets anything, so the events that were really important to us and made some influence are also recorded and become part of its calculations. These things can be seen in hands. But none can say what events will be considered important and be recorded. For example, if a person gets his first job and this person considers it to be a very important moment, then it will be marked in his hand, otherwise not.