It is emotional conviction, after all, that convinces people that their religious beliefs are a form of knowledge rather than a matter of faith. At the same time, emotional truth can be one of the only ways to form an accurate opinion of many human phenomena. Attempting to determine the best course of action in a tense political situation, for example, depends upon emotional knowledge and conclusions. Human activities do not take place in an objective world, and though empirical and objective truth can be achieved through the perceptions of the senses and through reasoning, these will not apply to human situations without emotional tempering. Without a complete awareness and understanding of the emotional issues at work in a given scenario, other knowledge is virtually useless. That being said, emotion is the way of knowing that requires perhaps the most careful attention when what is being sought is true knowledge rather than simply a belief in truth. The emotionality of religious convictions and "knowledge" has already been detailed above, but there are many other ways that emotions can lead to belief rather than truth. This is the point behind the design of many scientific experiments, especially double-blind trials. In these scenarios, information regarding experimental subjects is hidden from researchers in order to keep their emotional desires from influencing the experiment's results. It is not that the scientists would necessarily alter their findings based on their expected or desired outcomes, but emotions can alter exception and reasoning if not checked.

Language/Symbols

The final way of knowing, language and symbols, can also be highly insidious when it comes to discovering real truth. The system of language and symbols that an individual learns in large part dictates the way they perceive and interact with the world, and can just as easily lead to misapprehensions and mistruths as it can to the transmission of truth. Still, language is an invaluable way of attaining knowledge and truth. It is, in fact, necessary...

The remaining "knowledge" would be purely instinctual: a plant might be recognized as poisonous and so be avoided, but there would not be any conscious connection of the dots. There would simply be a biological "don't eat" imperative associated with the planet. Language and symbolic thinking allow for complex thoughts and deeper development.
Language and symbols can also be highly limiting, however. There are large differences between certain families of languages, and also major differences in perception amongst the various cultures that produced these languages. Concepts that are highly important in English -- notions of time and sequence, for instance -- might not even exist in another language, making our truth of "yesterday" and "tomorrow" as concepts utterly false or misleading notions to another. At the same time, these limitations are also necessary in order for any solid worldview capable of abstract expression and thought to exist. Language, then, can be seen as the great facilitator of knowledge and a highly misleading force, making truth appear to exist when really many supposed "truths" are simply the best available explanations in a given linguistic or symbolic framework or worldview.

Conclusion

Each of the four ways of knowing -- sensory perceptions, reasoning and logic, emotions, and language and symbolic thinking -- are important in a discovery of the truth. Each of these ways of knowing must also be subjected to the scrutiny of the other ways, in order to account for each of their respective fallibilities. In this way, it can be seen that it is the relationship between these four ways of knowing that is of real importance, and not any particular or specific way of knowing. By combining the various ways of knowing, and becoming as well versed as possible in each way of knowing, a more accurate and objective -- and thus a more useful -- understanding of the world can be achieved.