# How reliable is logic?

The reasons I think that logic is not enough to find the truth are:

• I sometimes conclude that something is 100% true, and can be observed easily; as it is based on logic, and then people don't believe me
• I sometimes conclude that something is true (not necessarily 100% sure), and when I increase my knowledge, it turns out to be false

If logic is not always reliable (according to what I mentioned earlier), then how to know when it is reliable? or do we just believe until proven wrong?

• Logic is as reliable as the quality of the premises in the line of reasoning being analyzed. Commented Jul 24, 2022 at 2:33
• There is no such thing as LOGIC as a single entity. There are distinct types of LOGIC as there are distinct types of cars or plants. We find many people speaking like there is a LOGIC entity alone which is confusing people. In one type of logic we can prove a conclusion is valid but in a different logic system the same conclusion is false. So we must be clear on what we mean by LOGIC. Which one? There also seems to be confusion between so called logic being about validity alone as math teaches & content of the argument. Soundness expresses the argument is valid & premises are true. Commented Jul 24, 2022 at 5:56
• @AZeed Logic is 100% reliable as far as we can tell although we cannot tell very far. What is often not reliable, however, are the premises from which we have to start our logical reasoning. For example: (p1) If I see God, then God exists; (p2) I see God; (C) therefore, God exists. The reasoning is clearly logical and 100% reliable. However, the two premises are very possibly false, so the conclusion is also very possibly false. Commented Jul 24, 2022 at 9:39
• You mixed inductive logic with commonly denoted deductive logic from your 2 examples. As for deductive logic logicism (propounded by Frege, Russell) claims it's so reliable that even Kantian innate concepts such as natural numbers need to be defined through 2nd order predicate logic as a class of equinumerous classes thus almost all mathematics should be entirely based upon logic, though Russell eventually failed to do so as inevitable collapse occurs somewhere in his ramified class (type) theory together with famous Godel's incompleteness theorems. Neo-logicism is still pursuing same... Commented Jul 24, 2022 at 18:45
• I have nothing more to add addressing your specific question. Actually logic in philosophy normally denotes deductive logic, your examples are called inductive reasoning which is by its nature not reliable as you perhaps observed in your experiences. A related topic is famously called Hume's problem to expand this inductive non-reliability issue. You may just review the links and I believe they could easily sort out your puzzles... Commented Jul 25, 2022 at 1:49