Spiritual discernment has little to do with human reasoning or intelligence. In fact, this discernment is needed due to the limitations of the human mind.
Be not conformed to this world: but be ye transformed by the renewing of your mind, that ye may prove what is that good, and acceptable, and perfect, will of God. (Romans 12:2)
Discernment is not our conscience. The conscience cannot always be relied upon:
The Spirit clearly says that in later times some will abandon the faith and follow deceiving spiritsand things taught by demons. Such teachings come through hypocritical liars, whose consciences have been seared as with a hot iron. (1 Timothy 4:1-2)
We need God’s gift of discernment in order understand what is right and what is wrong, what is spiritual and what is of the flesh. The Apostle Paul writes:
These things we also speak, not in words which man’s wisdom teaches but which the Holy[a]Spirit teaches, comparing spiritual things with spiritual. But the natural man does not receive the things of the Spirit of God, for they are foolishness to him; nor can he know them, because they are spiritually discerned. (1 Corinthians 2:13-14)
How do we obtain discernment? We cannot have it if we do not respect God and His commandments:
The fear of the Lord is the beginning of wisdom,
and knowledge of the Holy One is understanding. (Proverbs 9:10)
My people are destroyed for lack of knowledge;
because you have rejected knowledge,
I reject you from being a priest to me.
And since you have forgotten the law of your God,
I also will forget your children. (Hosea 4:6)
In order to obtain discernment we must humble ourselves before God and ask for it:
If any of you lacks wisdom, you should ask God, who gives generously to all without finding fault, and it will be given to you. 6 But when you ask, you must believe and not doubt, because the one who doubts is like a wave of the sea, blown and tossed by the wind. That person should not expect to receive anything from the Lord.8 Such a person is double-minded and unstable in all they do. (James 1:5-8)