Why Should We Prefer The Truth Over Falsehood?
Warning: Logic & Philosophy ahead.
(1) The ability to predict the outcomes of our (and others’) choices is useful because some outcomes are more desirable than others. See my previous post about this.
(2) Principle of explosion tells us that if we allow contradictions (meaning that a proposition can be both true and false at the same time) in a logical system, any proposition can be derived. For example, if we assume that both “All lemons are yellow” and “Not all lemons are yellow” are true, we can logically conclude that “Santa Clause exists”. We can also logically conclude that “Santa Clause does not exist”. It sounds weird but it’s true. Check the Wikipedia page for details.
(3) It follows that contradictions eliminate our ability to make predictions (because every possibility is logically concluded). If a single contradiction is accepted, all ability to predict something specific about the future is lost.
(4) Now, the thing with the truth is that it can be rejected in multiple ways. If you disagree with “2 + 2 = 4”, you can do it in a number of ways: “2 + 2 = 5”, “2 + 2 = 0”, “2 + 2 = 10000.36” and so on. A person looking for the truth has no choice but to accept “2 + 2 = 4” but to someone looking for falsehood, many choices exist. Truth is very specific. Falsehood comes with a lot of diversity. Those different alternatives are very likely to be contradictory.
(5) Therefore a set of true statements is much more likely (even guaranteed, depending on your definition of “truth”) to be self-consistent and non-contradictory. A set of false statements (including the implicit premises) is very likely to contain contradictions. It can avoid contradictions only by becoming too vague to have any predictive power or by denying certain fundamental axioms that we take for granted a priori.
(6) Therefore, truth gives us the ability to predict the future with much more specificity and reliability than falsehood.
(7) Hence, we should prefer truth over falsehood.
(This analysis assumes that logic is the best way to derive conclusions from given premises. That argument too follows the same structure: Logic requires consistency. Without logic, one can reach any conclusion thus losing all predictive power. Now, it’d be interesting to think about what type of logic we ought to follow.)