Commonsense is a loosely defined term, much like many others we use routinely. For me commonsense has always implied the recognition and acknowledgement of that which is obviously, even intuitively true. It leads to the logical conclusion which the majority would reach, though a few deluded ones may see truth differently. The very word common suggests that commonsense should be the prevailing sense. Of course, if the majority define commonsense, then commonsense can change as the majority changes.
What further clouds the notion of a commonsense understanding is the obvious fact that many, maybe most of us, view our personal opinions on most subjects as the commonsense one, the one supported by undeniable logic and correctness. Thus commonsense by extension is nothing more than the reasoning which supports what I believe on the subject.
It would be hard to deny that what people believe to be obviously true is culturally conditioned. It takes little observation to note that the attitudes, thoughts, ideas, and beliefs that we hold here can be anathema to those of another cultural background.
For those of us who claim to embrace the Bible and Jesus, the idea of being guided by a commonsense approach is paradoxical. In both the Old and New Testaments we read how what man might see as reasonable and true and a proper reflection of ultimate reality is not. Isaiah 55:8 in the OT and much of what Jesus taught in the Sermon on the Mount (Matthew 5-7) would seriously challenge the idea that much of current day commonsense thinking leads to the truth. When the Apostle Paul pointed to the foolishness of preaching versus the wisdom of men in I Corinthians 1-2, he certainly did not seem to suggest that commonsense, as an expression of prevailing beliefs, would guide us to the truth. For those who call themselves Christians, commonsense in our normal understanding of the term, should be the last place to seek the truth.
Admittedly, I recognize two very different kinds of internal voices which strive to guide us in our lives. One is the ego, the one which relishes the whole concept of a commonsense reality, a reality which serves the self. The other voice emanates from the human heart and reflects the element of sacredness which each possesses as created in the image of God. The voice we normally recognize as commonsense is the former. The true wisdom of the ages is the latter. It is a common voice in the sense that each can hear it if they try, but it is decidedly uncommon in the sense that many fail to pay attention.