As Christians, we are to stand for truth, and especially Truth, despite the will of the crowd, the opinions of noisy people and the price we have to pay. It is a Scriptural duty to correct the errors of those who profess Christ, just as Paul rebuked Peter. So how do we know what is true and what is error? By discerning the truth in the light of Scripture and the Spirit.
There are three simple tests to determine truth using rational discernment. I'm not going to touch on spiritual discernment other than to point out its misuse since spiritual discernment in Scriptures does not contradict Scripture. For example:
Mat 16:15-17 He saith unto them, But whom say ye that I am? And Simon Peter answered and said, Thou art the Christ, the Son of the living God. And Jesus answered and said unto him, Blessed art thou, Simon Barjona: for flesh and blood hath not revealed it unto thee, but my Father which is in heaven.What are these three tests? They are the same ones I used in the example in the presuppositional lesson. One proviso in these tests relates to the seriousness of the issue. In my first example below, unless you are soliciting my advice on goat raising, it is a trivial matter and doesn't need such precision in discernment. However, in the second example below, that is a critical issue for Christian doctrine and requires much more precision.
1. What are the objective facts? This means getting down to the primary sources. If I say or write down as a fact that I am raising goats, then you should either be able to visit my place to see the goats I am raising or have verifiable evidence, like pictures, of the goats I am raising. If someone says that Jesus endorsed the OT eye for an eye laws, then they should be able to give a citation to that effect like:
Mat 5:38 Ye have heard that it hath been said, An eye for an eye, and a tooth for a tooth:See, it was just confirmed in Scripture, wasn't it? You should now go look at the Scripture as the primary source, and see what the context is:
Mat 5:38-42 “Ye have heard that it hath been said, An eye for an eye, and a tooth for a tooth:But I say unto you, That ye resist not evil: but whosoever shall smite thee on thy right cheek, turn to him the other also. And if any man will sue thee at the law, and take away thy coat, let him have thy cloke also. And whosoever shall compel thee to go a mile, go with him twain. Give to him that asketh thee, and from him that would borrow of thee turn not thou away.Aha! It seems this position is untrue and quoted out of context, which if very common among false teachers since full disclosure and operating in the open would destroy their teachings, but to discern this, you must check the primary sources. Otherwise you are just basing your acceptance (or rejection) on hearsay. Depending on the seriousness of the issue, hearsay may be acceptable, but if it is serious, then even if you implicitly trust your nonprimary source, it is your responsibility to check the objective facts from primary sources before making a call on the subject on nontrivial (salvation, doctrine, etc.) issues.
2. What is the quality of the testimony? Character counts. If the one providing the witness is a known liar, then you should obviously not weight his evidence as much in comparison with someone well known for their truthfulness. Look at what style the “evidence” takes, if it is sketchy and contradicted, gossipy sounding or way over the top, look even closer. Ask what price the witness paid for giving his testimony. Ask if there were any material rewards for giving the testimony he did. If you see lots of ignoring of critical points, refusal to do anything more than assert or accuse, appeals to bad logic or incorrect axioms, ranting, changing of the testimony (especially to make it 'stronger' relevant to the position being claimed), etc., then you should question or discount the testimony you are receiving from this witness. If they are unfaithful in small things, can they be trusted in large ones? See Matthew 25:21, 23 and Luke 16:10-12
3. Apply Occam's Razor. The simplest explanation is virtually always the correct one. Even involved issues can have a simple explanation. One favorite conspiracy concerns the oil companies and their constant “gouging” of the public. Yes, they are in it for the money and yes, it is their duty to their stockholders to maximize profits, but on the ground at the gas pumps, the oil companies often have little to do with the price. If four stations are along a street and one raises prices, then invariably the rest will follow suit. When I worked for 7-11, I saw it all the time. The manager would drive by the oil company station and then raise/lower our prices to be one cent cheaper than they had. Nothing changed about the gas in our tanks, but it gave us the reputation of being the cheapest on gas. For the last few hurricanes, the distributors (not the oil companies themselves) chose not to lay on extra trucks to meet demand locally claiming that they had to “keep reserves”. So for the day or so before a hurricane, prices jump up by a large margin, unleaded runs out and only midgrade or high octane are available. Within a day or two of the storm making landfall, prices drop and unleaded becomes available again. For the conspiracy theorist, it must all be the evil CEOs of the oil companies or their master who is controlling every last gas pump price in the world. So watch for the moving goalposts, the quoting out of context (“a text out of context is a pretext for a proof text”), requirements for enormous complicated conspiracy theories, etc.
Remember that no lie can be of the truth and wherever a fundamental doctrine is denied or twisted, even if it is just one little thing, eventually all of the fundamentals of Christianity will be denied since a little leaven will leaven the entire lump.