I remember the first time I saw something invisible change the visible! Have you ever seen a candle go out with invisible carbon dioxide gas? You could not see the carbon dioxide gas, but you could see the irrefutable change that it brought upon the candle flame! Also like putting a candle in a jar with the lid on, watching it starve, therefore, proving the reality of oxygen. 

There are at least 50 verses in the Bible that talk about blindness. It’s interesting to read Jesus’ interaction with the spectrum of religious and non-religious in the New Testament. Who did he have a harder time with? Who did Jesus push back most against? Time and time again it was those you should have seen, but did not. What about you and me? Are we claiming to see and perhaps missing most important?