The Psalmist hates vain thoughts, but loves God’s Law. (Ps 119:113) To hate vain thoughts, we must equip ourselves to detect invalid thought patterns, especially within, and train ourselves to think the way God’s designed us to, asking Him to help us. (Ps 19:14)
From the contrast the Psalmist presents, vain thoughts seem to be any and all mental or emotional activity that’s inconsistent with God’s Law, or with truth. (Ps 119:142) Vain, empty, foolish thoughts would then include any notion or sentiment not springing from delight in God’s Law (Ro 7:22), or that’s inconsistent with Torah (Is 8:20), or trains of thought that are illogical (1Co 14:20) or irrational. (1Pe 1:13) This includes pride and presumption, all deception and all forms of faulty reasoning.
For example, my high school honors biology teacher dismissed Creation Science on the first day of class by asking all us young men to check if we were missing a rib. We all, myself included, laughed religious superstition to scorn: of course, if God took a rib from Adam to make Eve, then all men should be missing a rib. Case closed.
He then proceeded to teach us that biological traits are inherited through DNA, contradicting the very reasoning he had just used to dismiss Creation Science: if I lose a finger and then have kids, my kids will still have all their fingers. But we never noticed his error, because we wanted to believe in evolution.
It’s raw presumption to believe something simply because we want it to be true, and we’re all guilty of this at times. Whenever we’re biased, emotionally predisposed to accept or reject an idea, then we’re ripe for deception, and any pretense of evidence to support the lie will comfort and strengthen us in believing it. (2Ti 4:3) This is exactly how the enemy wars against us, taking us captive through deception. (2Ti 2:25)
To find the truth we have to want it, search for it, value it above all else: buy truth and sell it not. (Pr 23:23)
Logic is reasoning that enables us to discover truth, to learn new truths based on what we already know to be true. Like mathematics, it always works because it’s blind to our desires. God has given it to us to help us pursue Him and His calling in us to subdue the earth. We can tell logic is of God because He never violates it, and because we don’t either when we’re unbiased; we’re easily able to identify false reasoning when someone tries to use it to discredit something we want to believe or already know to be true.
There’s a moral integrity and wisdom here that very few seem to find. Because we’re all born broken, dishonest and selfish, dead in our trespasses and sins (Eph 2:1), we all have difficulty discerning truth in spiritual things because we are emotionally biased against them, and the enemy is constantly trying to deceive us, throw us off balance, and take us down. Even when we’re well-trained and being as careful as we can be, we can still slip into pride and make careless mistakes in our reasoning. These errors can be very hard for us to see on our own (Ps 19:12), so we need others to help us in our journey, to wake us up, and encourage us to shake off the stupor and walk in the light. (Ep 5:15)
If we’re to love God and His ways, we ought to hate every false way (Ps 119:104), and not be counted among the proud, foolish and thoughtless. (Ep 5:15) Humility is open to criticism, to being challenged on every belief and why it’s being held. Sometimes, it’s those who disagree with us who can help us the most. Don’t fear being wrong, only staying that way.