[Hu]mankind is not the rational animal; he is the potentially rational animal. He can be every bit as reactionary and mindless as any other animal; however, man has the capability to reason which takes more effort, or can just react which is easier. Whether through reason or some non-reasoning method, we can claim knowledge, rightly or wrongly.
The way by which we gain knowledge comes in one of three different ways: by revelation; by experience; by authority. These each have their respective place in the accumulation of knowledge, but that does not mean they have equal value. They differ in where the origination of knowledge comes and from where it is understood.
Revelation is the formulation of an idea without empirical input; it is generally sudden and taken as divinely inspired. or a 'gut feeling'. Most often, this is embraced through the emotional experience that one 'felt' the presence of God, and therefore how correct is the knowledge. There is a second kind of revelation that is not actually revelation, though it gets attributed the same - that type will be addressed later.
Experience is based in empiricism, and expanded to concept formation through processing and contemplation (i.e. reasoning), that can again be affected by empirical findings. Things are expected to be and act in accordance to how our experience of them says they should be, with the expectation that things of a similar nature will act in a similar way unless there are other factors to understand before a different expectation can be expected: e.g. we know that water will freeze at a certain temperature and know that all liquids will also freeze, unless there is something else to change the results, such as a sufficient amount of alcohol to prevent freezing of the liquid.
Authority is the taking of knowledge as granted by another, because they said so. A minimum degree of ethos is granted to whomever, and from that we take their word that what they say is true because their ethos grants them that status. For example, if the question was regarding the nature of volcanoes, a vulcanologist would be best, though because of the nature of scientific inquiry and the related aspects of the fields, a geologist's advice would (should) be more valuable than the advice of one whose specialty is in medieval literature. It is expected that whoever is talking, knows their field well enough to be able to speak from and about it.
Revelation is by itself in that it can be wholly subjective. There does not need to be any reference to empirical validation in any way as the verification of the knowledge through revelation is the emotional sensation that accompanies it. Experience necessarily is objectively based as it is empirical, for one experienced a thing or event and takes the learned information through sensory organs to store for processing and later retrieval. Though the interpretation may have subjective elements, it is based upon an objective event in order to be interpreted. Authority is the deferment of either revelation or experience, granting the knowledge to a third party as a valid source to speak on behalf of actually having the revelation or the experience.
Most of the knowledge we have is based upon authority. Believe that the Koran or Bible is the word of God?-that is based upon authority. If one believes they actually existed according to their respective texts, no one is alive today who spoke to Moses, Jesus or Muhammad, or witnessed any of the acts or 'miracles' they are purported to have done (one reading this definitely did not see them), so authority is granted to those who told the believer: that would be the messengers of today, and the long line of authors who transcribed and 'spread the word' ultimately to the authors themselves. Each has to be granted authority to believe what is read is actually real. Believe in the theory of evolution?-unless you are a scientist working on the theory, your belief in evolution is based upon authority. If you did not conduct the experiments, you grant authority to those who did perform the experiments; authority would still be granted to others in one's field of study. But whether this is from another’s revelation or experience, as a deferment the issue remains that the one who originated that which is taken as knowledge either did so based upon their subjectively or objectively-based perception of reality.
This brings up the crucial distinction between revelation and experience, whether one’s own or deferred through authority: it is the difference between that which is verifiable and that which isn’t. Experience is that which any may have and come up with similar results – the more similar the variables, the more similar the results. For example, if different people take a certain amount of water with the same composition and apply the same heat to it in the same environment, it will turn to vapor in nearly the exact same manner; however, if some variable changes through different attempts, such as the environment in elevation then there will be a change in the results by some degree. The more variables that are introduced, the greater the variability in results, such as different chemical makeup, heat source and the like. Anybody can take the same events and variables and come to the same conclusions. The issue in life is finding the appropriate variables, and reading them properly.
Revelation is not tied to experience of the world, but of a feeling of something inside oneself. There is no way to confirm it, for it is wholly subjective; there is nothing that anyone else can do to verify one’s revelation, for by the nature of revelation it is granting authority to one who said they had it. There is no way to externally verify it. Revelation is actually a claim to come to knowledge from an outside source, but without experience of any means of accumulating or transmitting said knowledge; it is to be a direct inspiration from God or another divine source directly into one’s mind/soul. How can an individual attest to that the revelation was correct?-he ‘feels’ it, but how does he know that feeling is correct? There is nothing outside of that feeling. If they point to an external source, then it is experience and subject to interpretation.
This brings us to our last point: regardless of whether it is through revelation, experience or authority, each method of accumulating and processing knowledge is done through our mental makeup from our biology, evolution, society, education and more: the base from which we make our understanding of what we take as knowledge. For experience, it is the reason why we know nature is not playing tricks upon us when we see a bent stick when it is partially submerged in water; for revelation, it is the reason why remote and primitive tribes who never heard of Christianity or Islam don’t attribute their revelations to Jesus, Muhammad or other Abahamic figures, but to their own interpretations of divinity – the reverse is true with why Christians and Muslims don’t attribute their revelations to the deities of those remote and primitive tribesmen.
Each level has its potential for contributing to knowledge in its own way: experience is limited to what we have done ourselves; authority is letting the expertise that another has earned contribute to our knowledge; revelation, on the other hand, is valid in one way that is not true revelation but how it can actually come about and that is as any knowledge gained is based and filtered through our mental maps (schemata) what is taken as revelation is the subconscious connections that exist within our minds – not actually ‘divine inspiration’ but the attempts at making connections that haven’t been made yet. Newton’s realization of gravity from the apple falling is such an example – it wasn’t a wholly new idea, but the culmination of ideas he had been reviewing beforehand that got the last piece added to complete the picture’s organization.
This is important for any level may be improperly attributed, leading to invalid conclusions and false knowledge. This is most readily apparent with revelation – especially divinely inspired – for there is no way that it can be verified. One says he felt the hand of God – how can that be proven or disproven? Equally, I can say I felt that his feeling was actually a gremlin making him believe it was God’s presence to try and trick him – how could I prove what I said, or be disproven? For both claims, as Hitchens quipped: what is advanced without evidence can be dismissed without evidence. This does not mean that experience and authority are immune to error. Science is never fully settled, and phrenology is an example of what was scientific at one point, but found to be erroneous at a later time. Where revelation cannot be reviewed; experience through science can be amended.
It is up to us to recognize how we get knowledge and where that knowledge comes from. This is especially the case granting authority for the one relaying knowledge does so based upon their understanding, in addition to their bias and interest in the world. Just as we each have our cognitive maps through which we interpret things, so do any we grant authority – where did they get their knowledge they are trying to persuade us to accept?-are they trying to 'sell' us something?
Are we to believe the worldview of those who limit themselves to the information gathered from their culture only, in a dogmatic way that it was given to them from an original source of revelation meaning that it cannot be verified in any way?-are we to believe the politician who has a vested interest in us believing his side of an issue?-are we to believe the scientist speaking in his field of expertise? It is the difference between an illiterate tribesman from millenia ago as contrasted to Dawkins' and Hawking's findings in evolution and cosmology telling us how life and the universe came to be. Revelation or 'gut feelings' may coincide with truth, but to verify we go beyond. Being mindful does not involve thinking with one's gut.
Ultimately, it comes down to the distinction: know reality from reality or from those who say what is reality through a means not tied to reality. It is through this uncritical review where man can repeat like a parrot, or bark upon command, but not actually reason to come to the truth of a claim. This is why mankind is the potentially rational animal for though he can reason, he also has the greater sin in not living up to his potential - acting as humans are capable.