For a cause to effectively be examined, there must be a way to find its cause and its effects. A 'first cause' has no prior cause, thus logic can only deal with its effects, and not the first cause itself, as there is nothing before it to derive its attributes from. Evolutionary theory has prior species to derive base attributes that can be modified through mutations from. Abiogenesis has prior energy to derive the base attributes of life from. What does energy derive its attributes from? Logic cannot help us answer this question unless we discover something to have existed before energy; then it can be posed as to what that effect was caused by. You can attempt inductive logic to figure out the attributes of some initial cause...but the chances of you being right, even if you've put every last piece of existence into consideration, is less than worthwhile. This idea is akin to 'The tao that is named is not the eternal tao'. Nobody can ever know what started it all, as there is nothing before it to set the stage for examination through logic. It's very much a, 'Alright, something started this ****heap called existence, but we can never know just what it was' sort of deal.