Preamble

Relativity of truth in common usage of the word

Truth is the state of being true, or a belief accepted as being true [1].

But how about the actual truth?

That assumes an unbiased all-knowing perspective, or a "God's eye view", if you wish. We do not have access to that perspective, regardless of our individual beliefs. Therefore, in everyday usage of the word, 'truth' is unfortunately a matter of perspective. That seems paradoxical and is in no way an attempt at diluting certainty of facts compared to opinions, but makes more sense when you consider the notion that it is defined as independent of perspective (absolute), but referred to in a subjective manner (relative).

Ranking Certainty

Since it is a perspective, I know that there's a strong possibility of my view being biased. The certainty or confidence I have in my beliefs is a spectrum based on multiple factors. They have a cumulative impact, weighed in descending order as follows:

1. Logical & Mathematical Consistency:
   Logic's definition and classification may be open to debate, but I see this level of abstraction can be sufficient for this topic. This shall apply not just to the claim, but also all other supporting information considered as evidence.
   The decreasing order of certainty within this:
1. What I understand in detail.
2. What I do not understand in detail, but I am convinced it is based on principles I understand, and the abstraction is justified given the support of majority of academic literature.
3. What I do not understand, but can see support of credible organisations (related to points below).
   
   
2. Scientific support:
   
1. Established Physics and Chemistry comes up as the highest priority after Logical and Mathematical consistency.
• Priority can be scaled depending on how indirect the claim is from the established hard sciences.
2. Evidence Pyramid System:
   For complex systems and topics where the fundamentals may be known, but they may be far removed from fundamental hard sciences, like medicine: it appears there's a good framework in existence: I favour the classifications used in Evidence Based Medicine [2], with one visual representation being the "Evidence Pyramid" [3] . The rationale being there's more scrutiny, larger and more diverse data-sets as we move from bottom to top of the pyramid.
   

   

   Evidence Pyramid [3]
   
   

• For evidence based medicine, the illustration may be directly used as a reference, but for other domains, similar strategies can be followed where such information is available.
• The weight is also scaled by factors like number of unique sources, sample size, timeline relevancy, population relevance, etc.
• When it comes to softer sciences, where even a looser version of Evidence Pyramid cannot be applied, I'm apprehensive and have a lower confidence in certainty of claims from even experts in the field taken too seriously. That being said, I'd trust the experts in the field (academics, researchers, practitioners) more than the average person unless their claims contradict harder sciences.
• Sometime it may seem to contradict harder sciences, but upon closer inspection it doesn't, so I'd give the benefit of doubt to the experts unless they do a poor job at explaining it when directly confronted with the dilemma.
3. Expertise from organisations and experts in the irrelevant field:
   Expertise usually involves formal training and peer-reviewed contributions in specific fields, and so claims from an expert in field A about a field be in which they have no expertise isn't treated the same way, but if they use scientific means, I'd still consider them as a low weighing scientific support.
   It's worth noting that a lot of work involving experts in a field branching out to another field in good faith and as a logical extension of their own field can be weighted far more heavily. 
• Example of credible expertise in different field: Edward Witten's work in physics forced him to expand the mathematical tools, as they were insufficient for him to continue. But his credibility is same or better as his credibility in mathematics, proven by the fact that he won the high coveted Fields Medal in mathematics, being the first physicist to have that honour.
• Example of poor expertise in different field: Kary Mullis, the Nobel Prize winning inventor of Polymerase Chain Reaction, went on to make various dubious claims ranging from alien abduction and talking to animals, to astrology with very little evidence. 
  
  
3. Observational Support:
1. My own physical senses in the moment.
• Unless my biological senses are known to be compromised (hallucinations or illusions).
2. Machine recorded evidence.
• Artificial manipulation must have been ruled out probabilistically.
• Artificial manipulation must have been ruled out through insufficient motivation to do so: helps if multiple independent diverse set of sources come up with similar evidence.
3. First-hand accounts in the moment.
• Unless biological senses are known to be compromised (hallucinations or illusions).
• Manipulation must have been ruled out probabilistically.
• Manipulation or biases must have been ruled out through insufficient motivation to do so: helps if multiple independent diverse set of sources come up with similar evidence.
4. My own memory
• Priority to most recent memories.
• Unless thought to be biologically compromised in the moment of observation.
5. Printed formal sources*.
1. Multiple Independent outlets with independent sources.
2. Governmental or Organisational Authorities.
6. Indirect individual accounts* (second hand accounts onward)
   
• I appreciate printed formal sources can be just this, but would consider them more credible due to the existence of systemic processes and accountability, even if they may be poor.
  
  
4. Unscientific Extrapolations
1. Anecdotal extrapolations and Perceived popular beliefs.
• The reason why this scores low is because humans are bad at natural extrapolations: Example: Getting robbed in a city does not add more weight to the notion that the city has high crime rate if there's stats to show otherwise. At the same time, I will not deny that I got robbed because of the stats
2. Intuition.
• I consider this a subconscious (or is it unconscious?) extrapolations based on observations (direct and indirect) and inference.
• The point I want to highlight is that this whole system of ranking certainty is a conscious process, and intuition isn't, even though they both originate in our own minds: it makes all the difference!

*Trust is developed through assessment of past performance, potential conflict of interests, coherence to logic, known localised biases, etc.

Dynamic updates

I try to be open to the idea of my previously held belief being wrong. Because the change may have far reaching effects, I tend to scrutinize suggestions that can potentially topple my long held and/or fundamental beliefs more than others.

As such, you will also see edits to my posts that may, on occasion, contradict my previous beliefs.

Painting reality

Well, that's the fundamental premise upon which I try to paint my reality in this blog.

References:

[1]: Oxford English Dictionary

[2]: University of Oxford, Oxford Centre for Evidence-based Medicine – Levels of Evidence (March 2009) 

[3]: Dartmouth Biomedical Libraries: Evidence-Based Medicine (EBM) Resources