Isn't challenging dogma considered heresy?
Only in heavily top-down power structures that think that only THEY have the keys to the kingdom.
Here are some Scriptures that show that THINKING is permitted...
NIV Matthew 17:25
"Yes, he does," he replied. When Peter came into the house, Jesus was the first to speak. "What do you think, Simon?" he asked. "From whom do the kings of the earth collect duty and taxes--from their own sons or from others?"
"What do you think? If a man owns a hundred sheep, and one of them wanders away, will he not leave the ninety-nine on the hills and go to look for the one that wandered off?
"What do you think? There was a man who had two sons. He went to the first and said, `Son, go and work today in the vineyard.'
"What do you think about the Christ? Whose son is he?" "The son of David," they replied.
30. In reply Jesus said: "A man was going down from Jerusalem to Jericho, when he fell into the hands of robbers. They stripped him of his clothes, beat him and went away, leaving him half dead.
31. A priest happened to be going down the same road, and when he saw the man, he passed by on the other side.
32. So too, a Levite, when he came to the place and saw him, passed by on the other side.
33. But a Samaritan, as he traveled, came where the man was; and when he saw him, he took pity on him.
34. He went to him and bandaged his wounds, pouring on oil and wine. Then he put the man on his own donkey, took him to an inn and took care of him.
35. The next day he took out two silver coins and gave them to the innkeeper. `Look after him,' he said, `and when I return, I will reimburse you for any extra expense you may have.'
36. "Which of these three do you think was a neighbor to the man who fell into the hands of robbers?"
37. The expert in the law replied, "The one who had mercy on him." Jesus told him, "Go and do likewise."
1. Now there were some present at that time who told Jesus about the Galileans whose blood Pilate had mixed with their sacrifices.
2. Jesus answered, "Do you think that these Galileans were worse sinners than all the other Galileans because they suffered this way?
3. I tell you, no! But unless you repent, you too will all perish.
4. Or those eighteen who died when the tower in Siloam fell on them--do you think they were more guilty than all the others living in Jerusalem?
5. I tell you, no! But unless you repent, you too will all perish."
20. For since the creation of the world God's invisible qualities--his eternal power and divine nature--have been clearly seen, being understood from what has been made, so that men are without excuse.
21. For although they knew God, they neither glorified him as God nor gave thanks to him, but their thinking became futile and their foolish hearts were darkened.
20. Brothers, stop thinking like children. In regard to evil be infants, but in your thinking be adults.
14. I press on toward the goal to win the prize for which God has called me heavenward in Christ Jesus.
15. All of us who are mature should take such a view of things. And if on some point you think differently, that too God will make clear to you.
8. Finally, brothers, whatever is true, whatever is noble, whatever is right, whatever is pure, whatever is lovely, whatever is admirable--if anything is excellent or praiseworthy--think about such things.
13. For we do not write you anything you cannot read or understand. And I hope that,
14. as you have understood us in part, you will come to understand fully that you can boast of us just as we will boast of you in the day of the Lord Jesus.