Suppose that you observe what appears to be a man walking what appears to be a male dog. While you stand silently, you observe the man turn his head towards you and then change his walking direction towards you. The man stops walking in front of you and says, “Hello, I’m Richard, and this is my dog, Jabberwocky.”
There are some facts which may be deduced from these observations. These deductions are absolutely certain and 100% trustworthy because they are the observations. These facts are:
1. You observed what appeared to be a man walking what appeared to be a male dog.
2. While you stood silently, you observed the man turn his head towards you and then change his walking direction towards you.
3. You then observed the man stopping in front of you and saying, “Hello, I’m Richard, and this is my dog, Jabberwocky.
There are also many facts which may be INduced from these observations. These inductions are facts which require other facts to be true in order to be true. The inductions with the highest level of certainty are those for which the other facts upon which they rely are firmly established and reproducible scientific facts. Examples of these highly certain inductions are as follows:
1. The man and dog possess mass and are acted upon by gravity which can be induced by accepting that classical mechanics apply well to the situation, and by recalling that the man and dog did not fly away after pressing their feet down during the walking motion.
2. The man possessed a beating heart which can be induced from the man’s apparent vitality, ability to walk, and lack of distress.
3. The man was capable of seeing which may be induced from the turning of the head while you stood silently and the known operation of the sense of sight
4. The man has lungs, which may be induced from his apparent ability to speak, and because he appeared to be a human male which are well known to have lungs.
And there are still many others. The next set of facts are those which rely upon past experience and/or the trustworthiness of others. These are inherently less certain and trustworthy then the previously established groups of facts. Examples of these types of inductions are:
1. The man speaks and understands the english language, which is induced from past experience of people that have recited complete and intelligible english sentences can speak and understand english.
2. The dog’s name is Jabberwocky, which relies upon the man knowing and telling the truth.
3. The dog belongs to the man, which relies upon the dog and man walking together, and the man seemingly knowing the dog’s name, and an assumption that the man is walking someone else’s dog.
4. The man was not nude, which relies upon the fact that you did not note that the man was nude in the observations and that it has not been your experience to see any men walking their dogs in the nude.
5. The man’s name is Richard, which relies on the man knowing and telling the truth.
6. You and the man had not previously met, which relies upon your experience that people that you have already met tend not to reintroduce themselves upon meeting again.
And countless others. Many of the inductions in this group would reasonably require further investigation to improve their certainty or trustworthiness before they may be firmly relied upon for subsequent decisions.
And that is how a rationalist establishes and ranks the reliability of facts. If you are anything like me, you might be thinking, “OK, what other possible methods of establishing facts exist?”
There are other epistemological approaches. Suppose you met someone that was read the same few sentences of observations and you asked what facts they had learned and they said, “Richard is a good man.” Well, you might wonder what that is supposed to mean and ask, “What? Why?” To which they may well respond, “It makes me happy to meet other dog walkers, Richard made me happy, and so, Richard is good.” In this case the other person seems to be drawing conclusions about the outside world from their own internal emotions while simultaneously accepting past experiences and Richard’s trustworthiness as completely certain. And, as you may surmise, it may be very difficult for a rationalist to carry out a debate that doesn’t end in mutual confusion with someone with such a vastly different epistemology.