Truth

What is "truth"? Are some things more important than knowing the truth? Or telling the truth? See also: What is most important?
== What is meant by the word "truth"? ==
Truth is when we create a model of reality, a hypothesis, and it matches reality (rather than mismatching, being contrary to reality). 
See also: 
* Sense And Goodness Without God, section 2.2.6, Facts and Hypotheses
* here's the LessWrong guy's take on the subject, which is even longer than most of the things he writes! And uses morbid humor against his intellectual opponents!
* my page about what the word "reality" means.
== How to figure out what is true? ==
See:
* my page about Epistemology
* Figuring out what is true
== Do we need to use truth? ==
Can we use lies instead? What about half truths? Or something we think is close enough?
What about ideas like "it doesn’t matter if astrology is real; it matters if it’s useful"?
In the hierarchy of values, honesty is below compassion and reasonableness. It is sometimes either uncompassionate or unreasonable to be honest (or fully honest). But for many reasons I think that's rarely the case in important matters.
In our own heads, it is most reasonable and compassionate towards ourselves to know the truth, nearly in every case.
See also:
* Richard Carrier's The Real Basis of a Moral World:
"any system of false beliefs is doomed also to have many side effects that are damaging or even ruinous of human satisfaction, bringing about unexamined or unexpected harms and failures. Because it is impossible to design any epistemology that only conveniently ever discovers harmless or helpful false beliefs. Which means, while you are deploying the epistemology you need to get people to believe what you suppose to be harmless or helpful false beliefs, you and they will also be accumulating with that same epistemology many other false beliefs, which won’t just conveniently be harmless or helpful. “Ideological pollution,” as it were. You need a cleaner source of ideas. Otherwise you just make things worse and worse. Whereas any epistemology that will protect you from harmful false beliefs, will inevitably expose even the helpful and harmless ones as false"and What's the Harm?
See also:
*The overlap of decision-making and figuring out what is true
*many of the memes that are basically confessions
*Die, "Noble" Lie!
== The Future and Choice ==
Two related areas where the truth can trip-up our simple notions are the future and choice.
Can we choose what we want to be true? Sometimes. That's what every single choice is inherently about. [some may wish to read up on compatibilist free will here. the entire debate about free will might be partly due to this exact trip-up regarding truth and choice, and/or vice versa]
And that entire human thing is going to be connected here. The things we create. An obvious example would be the laws of our governments. [and, interestingly, even human language and philosophy is a human creation, including our philosophy of truth, see Epistemological Endgame][though some may wonder how much conscious choice was involved with the evolution of some human stuff].
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