I don’t remember in what math course we are first introduced to imaginary numbers, but if you stick around math classes long enough you will meet them. As a refresher, an imaginary number (represented by the letter i), is equal to the square root of negative one. Since any number, positive or negative, multiplied by itself is equal to a positive number, it follows that you can only go in reverse by taking a square root of a positive number. The square root of a negative number is a contradiction, hence the term imaginary number.
Despite it’s “non-reality” imaginary numbers are useful in math and science because they allow the construction of non-real complex numbers which have certain scientific and engineering applications. In other words, the concept of the imaginary number was invented not because it is is seen in reality but because it is useful.
In recent years, so-called homosexual marriage has become a cultural equivalent to the imaginary number. This imaginary marriage does not exist in reality, but is a construct that certain people (activists, legislators and judges to start) have decided is culturally useful to them. The fact that it is imaginary and not real is not important to them, because they do not understand the difference, just as most of them don’t know the math equivalent. And that seems to me the key problem – how does one engage rationally about so-called homosexual marriage with people who don’t know they are using imaginary numbers?