Q.Planted 2 seeds of corn together now 4\
In my garden I planted sweet corn, 2 seeds per hole, now the plants are 4″ high and I am wondering if I should thin to 1 plant each.

Certified GKH Gardening Expert
They, actually, don't seem to mind being planted close such as this. If you feel that they are being constricted and affected by this, then you can pinch one of the tops off while leaving the roots in ground. This will avoid disturbing and killing the corn that you intend to keep.
I would leave it alone, though. They can usually do just fine like this.
This article will help: https://www.gardeningknowhow.com/edible/vegetables/corn/grow-sweet-corn.htm