Truth

There are two basic questions about truth - where is the source of truth and where is truth located.  The answers to both questions is either internal or external.  Based on the answers to these questions, we can classify belief systems.

external source, external location:  traditional Christianity, traditional Islam, Western empiricism

internal source, external location:  Plato, modern Christianity, Mu'tazila Islam, Sufi Islam, rationalism, modernism

external source, internal location:  Old Testament

internal source, internal location:  Talmudic Judaism, post-modernism

The first question is easier to understand.  External sources for truth include empirical evidence and scripture.  Internal sources for truth include reason and spiritual inspiration.  Traditional religions focus on scripture.  Empiricism, including most science, focuses on empirical evidence.  The Old Testament combines both by having a scripture that argues empirically.  Plato, Mu'tazila, rationalism, modernism, and Talmudic Judaism use reason as their source of truth.  Modern Christianity, Sufi Islam, and various other crazy religions believe that people can find truth by supernatural inspiration.

On this first question, I strongly support external sources of truth and oppose internal sources of truth.  Internal sources of truth will always end up serving to rationalize whatever people want to believe.  It makes little difference whether the method is reason or supernatural inspiration, the result is the same.  One can see this today in the shared insane beliefs of modern Christians and secular modernists.  Of the external sources, I prefer empirical evidence for the highly intelligent, and prefer scripture for everyone else.  But both are valid.  Scripture is stable and is tested over time.  Religious books that don't work are selected out by the historical evolution of religions, so scriptures that are old tend to be valid.

The second question is very hard for most people to understand.  This is because Western culture is all based on Plato where truth is located externally and is understood based on the correspondence theory of truth.  The alternative is that truth is internal, located in your mind.  I am not going to try to fully explain this here, but to try to understand it, you can read The Philosophy of Hebrew Scripture and Zen and the Art of Motorcycle Maintenance.  The result of this view is relativism which allows one to tolerate other views.  In the case of Talmudic Judaism, truth is relative to the group of people and Jews have their own truth and what everyone else believes is irrelevant.  This allows them to function as successful parasites within other cultures with differing beliefs.  Post-modernism is less coherent but they basically view truth as subjective.  In other words, truth is whatever you want to believe is true.  I would describe this belief as temporary cultural insanity which will soon be wiped out, so it isn't very relevant.  The Old Testament considers any belief system valid that works over the long term.  This is confirmed in the The Rechabites’ Example.

Two related concepts are absolute versus relative and objective versus subjective.  To say that truth is located externally is to believe in absolute truth, while saying that truth is located internally is to believe in relative truth.  An external source of truth implies that there is an objective standard for truth, while an internal source of truth implies that truth is subjective.  So external source and external location, like classical Western empiricism, means objective absolute truth.  The systems with internal source and external location are actually subjective absolute truth which sounds like a contradiction because it really is nonsense.  In other words, these systems determine what they consider to be absolute truth using subjective means.  The result is intolerant advocacy of insane beliefs, as can be seen in modern culture.  Internal source and internal location means subjective relative truth.  In the case of Talmudic Judaism, truth is relative to Jews as a group and is subjective based on the collective reasoning of the rabbis.  So this kind of works because it is at a group level.  In the case of post-modernism, truth is relative to the individual and subjectively determined by the individual.  This won't last long.  And finally, the Old Testament is external source and internal location, so objective relative truth.  Even though truth is relative, it can be judged objectively based on real world performance.  This means that multiple conflicting belief systems can be true for different people without a problem.  But any belief system that fails to meet the expectations of those who hold it in the long run are objectively false.

Normally I don't write about philosophy both because it tends to be irrelevant and because most people can't understand my views.  But in this case there is a very practical implication.  Because very few people follow the Old Testament, we must ally with another group to survive.  For this to work, it is essential that our truth is external source and internal location, and that the group that we ally with has a truth that is external source.  The latter point is easy to understand because only external source truth works in the long run in the real world.  But the first point, our truth, is critical because unless we believe internal location, meaning relative truth, we will not really be capable of properly respecting another religion.  I can respect Islam as a relative truth for Muslims, a truth that works for them, but that I don't share.

I mostly agree with everything that you have said. However, even with external sources of truth, there is a danger of people rationalizing what they want to believe. In many cases there is a limited amount of data that is not enough to make accurate inferences, and faulty assumptions are often made based on faulty empirical observatory. For example, back in the 19th and early 20th centuries, there was a theory called the "Expanding Earth Theory," that the Earth was increasing in size based on geological observations that were actually caused by shifting tectonic plates. Of course, from a logical point of view, the Expanding Earth Theory makes no sense, because the amount of material from outer space that arrives on Earth (such as meteorites) is tiny compared to the mass of the earth. In my opinion, it is ideal to make observation and theories based on an external source (empirical evidence), but also test them for logical validity with internal reasoning.

qwerty wrote

Of course, from a logical point of view, the Expanding Earth Theory makes no sense, because the amount of material from outer space that arrives on Earth (such as meteorites) is tiny compared to the mass of the earth.

I never heard of this theory, but actually your argument doesn't work because the Earth could expand if its density was dropping.

In my opinion, it is ideal to make observation and theories based on an external source (empirical evidence), but also test them for logical validity with internal reasoning.

Logic should never be used for more than forming hypotheses.  Some things that are true appear to be logically invalid.  For example the result of the single photon version of the double-slit experiment.

https://en.wikipedia.org/wiki/Double-slit_experiment#Interference_of_individual_particles

The problem here is applying logic to things that our minds can't fully grasp, like the true nature of light.  This is why we should always put empirical evidence over reasoning.

Yeah, the density of the earth could theoretically decrease, but it wouldn't happen until the chemical composition of the inner earth is changing, which is extremely unlikely. As for the double-slit experiment, there could be additional scientific research in the future which helps us understand the nature of light in ways that we can't understand it now. And yeah, I generally agree that we should rely on empirical evidence first for knowledge.

We can mention here the Michelson Morley_experiment where the scientific community failed to interpret the results of the experiment correctly (only after 20 years). simply because they held to theory of the aether too strictly. so instead of having doubts on the theory, they had doubt on the experiment itself (not accurate enough).
I think we can learn from that, that we should not attach too strongly to our current understanding, and not to crystallized our thoughts.