It seems you are questioning the reliability of using 'testimony' or 'observation' as an evidence for an argument/event. I I will use my own 'observation' to offer a possible solution to this question.

According to my experience, there are situations where you could only know the full truth, if you at least believed/assumed the partial truth. For example, in a mathematical inequality equation, you would substitute a number and assume it to be true; and if x is true, then x must be true for all situations (that satisfy the conditions) else x is false.

Now I'm going to answer, using deductive reasoning derived from sensory observation of partial/uncertain truths:

Empirical data based from observation is reliable and strong evidence.
There is limited things/events which a person can observe within his field of sensory-experience.
A person can't observe everything, sometimes he must rely on others observation to get information.
This is secondary information, which 'truth' can get stained by other person's personal interpretation.
Assume: We need all information we can get for humanity to progress and for civilization to evolve.

Conclusion: We need to trust other person's observation, test its truthfulness, build new ideas around it. Even if it means accepting 'truth' that is uncertain, even if 'truth' is primitive or imperfect, even if it means getting the 'truth' contaminated by bias and subjective interpretation. As long as this 'truth' can be useful, we can rely on other person's 'truth' and learn new things.

Because nature always tries to attain a state of equilibrium, escaping from the path of chaos so it can eventually attain relative perfection and stability.
Yeah that's right, those balances are actually the result of evolution. Nature is so awesomely designed that it is the only program in the matrix that supports all kinds of life and have the ability to update itself. I wonder who designed this thing.

Allow me to define freedom on the hypothetical grounds of truth, beauty and goodness:
Freedom is having the ability to do 'good' anytime, anywhere without limit. Therefore any place that restricts and limits the application of goodness cannot be called 'free'.

I'm just gonna add a totally unrelated quote here:

If one must be absolutely free, then another must become an absolute slave.

Someone can score 5 but feel nothing about it, someone can score a 1 and have more tragic experiences than that, therefore this questionnaire is sometimes inaccurate.:
Someone can get a score of 2 and also experience something worse in their childhood like:

Living in a socially isolated, negatively influenced environment since childhood
Lasting chronic pain from childhood to adulthood,
Had no 'real friends' nor someone to empathize with
Lose faith in humanity at the age of 5
Get shouted, insulted every day for 2 years any etc...

Yeah, something like that.

Just finished reading Urantia Book
Now reading:
The Art of Loving by Erich Fromm