put another way, if a proposition is true, then it is true. So, if it is true that Barack Obama is the U.S. president, then it is true that he is the president. At first blush, this law may seem so simple and obvious as to be hardly worth stating. However, some very interesting and important philosophical problems turn on the truth of this law. And the other two laws of thought are actually derived from this one. This is why it is the most basic of the logical laws. Such are the basic laws of logic