Our conscience, as the Bible describes it, is not what we are thinking. It is the part of us that God gave us to discern good from evil & not violate what is good. When we do that our conscience convicts us that we have done wrong & need to be made right. If we continue to go against what we know is right, we can 'sear' our consciences, like with a hot iron, so it no longer convicts us of doing wrong.
It can also be deceived into thinking we are doing right if we keep believing a lie & training our conscience to say it is all right & good works when what we are doing in our flesh is evil or dead works. A conscience can be weak in a new believer learning about Christ or it can be strengthened through maturity & faith, making sure to keep it clean/clear/pure before God & men.
Doing a study on the conscience from Scripture can bring out the truth. The OP is just one passage. It should be viewed in light of the immediate context & also all the other correlating passages teaching on the conscience.
Here is just a sampling of passages that can open up a more indepth study about the conscience.
I Tim 1:5,6 Now the goal of the commandment is love, which comes from a pure heart & a good
conscience & a sincere (unhypocritical) faith. But some people have missed this whole point. They have turned away from these things & spend their time in meaningless discussions.
Rom 12:9 Love must be sincere. Detest what is evil; cling to what is good.
I Tim 3:8-10 Deacons likewise must be dignified, not double-tongued or given to much wine or greedy for money, but firmly holding to the mystery of the faith with a clear conscience. Additionally, they must first be tested. Then, if they are above reproach, let them serve as deacons.
I Tim 1:19,20 Timothy, my child, I entrust you with this command in keeping with the previous prophecies about you, so that by them you may fight the good fight, holding on to faith & a good conscience, which some have cast away (pushed off, rejected), & so doing have suffered shipwreck in regard to the faith.
I Cor 8:1-13 Now concerning food offered to idols: we know that “all of us possess knowledge.” This “knowledge” puffs up (makes us full of self-pride), but love builds up (edifies).
2If anyone imagines that he knows something, he does not yet know as he ought to know. But if anyone loves God, he is known by God.
4Therefore, as to the eating of food offered to idols, we know that “an idol has no real existence” & that “there is no God but one.”
5For although there may be so-called gods in heaven or on earth—as indeed there are many “gods” & many “lords”—yet for us there is one God, the Father, from whom are all things & for whom we exist & one Lord, Jesus Christ, through whom are all things & through whom we exist.
7However, not all possess this knowledge. But some, through former association with idols, eat food as really offered to an idol, & THEIR CONSCIENCE, BEING WEAK, is defiled.
8Food will not commend us to God. We are no worse off if we do not eat & no better off if we do. But take care that this right of yours does not somehow become a STUMBLING BLOCK to the weak.
10For if anyone sees you who have knowledge, eating in an idol’s temple, will he not be encouraged, if his CONSCIENCE IS WEAK, to eat food offered to idols?
11In that case, your knowledge is ruining a believer whose faith is weak, a believer for whom Christ died.
12Thus, sinning against your brothers
& WOUNDING their conscience when it is weak, you sin against Christ.
13Therefore, if food makes my brother stumble, I will never eat meat, lest I make my brother stumble.
I Cor 10:23-30 “All things are lawful,” but not all things are beneficial. “All things are lawful,” but not all things build up (edify). No one should seek his own good, but the good of others. Eat anything sold in the meat market without raising questions of conscience, for, “The earth is the Lord’s & the fullness thereof.”
If an unbeliever invites you to a meal and you want to go, eat anything set before you without raising questions of conscience. But if someone tells you, “This food was offered to idols,” then do not eat it, for the sake of the one who told you & for the sake of conscience—
the other one’s conscience, I mean, not your own. For why should my freedom be judged by someone else’s conscience? If I partake in the meal with thankfulness, why am I denounced because of that for which I give thanks? So whether you eat or drink or whatever you do, do it all to the glory of God.
Acts 24:15,16 And I have the same hope in God that they themselves cherish, that there will be a resurrection of both the righteous & the wicked. Because of this hope, I ALWAYS EXERCISE MYSELF, STRIVING TO MAINTAIN A CLEAR CONSCIENCE BEFORE GOD AND ALL PEOPLE.
I Tim 4:1-9 Now the Spirit expressly states that in later times some will abandon the faith to follow deceitful spirits & the teachings of demons, influenced by the hypocrisy of liars, WHOSE CONSCIENCES ARE SEARED (CAUTERIZED) AS WITH A HOT IRON.
3They will prohibit marriage & require abstinence from certain foods that God has created to be received with thanksgiving by those who believe & know the truth. For every creation of God is good & nothing that is received with thanksgiving should be rejected, because it is sanctified by the word of God & prayer.
6By pointing out these things to the brothers, you will be a good servant of Christ Jesus, nourished by the words of the faith & sound instruction you have followed.
7But reject irreverent & silly myths. Instead, train yourself for godliness. For physical exercise is of limited value, but godliness is valuable in every way, holding promise for the present life & for the one to come. This is a trustworthy saying, worthy of full acceptance.
What does it mean to have a seared conscience?
There are many more verses but time constrains me as to posting them & giving understanding. May the Lord open your minds to understand the Scriptures & in that understanding, obeying His commandments in His Word.
Baker's Evangelical Dictionary of Biblical Theology - Conscience