What philosophy has to do with the art of persuasion.
Understanding the Philosophy of any given idea will help us understand:
1) Ourselves: why we believe a given idea, how we came to believe it, how much we believe it. This helps us understand:
2) The Idea Itself: whether or not it is actually valid or true; is the idea persuasive and valid or just persuasive?
3) Other's Relationship to The Idea: why do people believe what they do about this given idea, what we need to do to convince others that our belief in the idea is accurate, valid, true?
To understand why ideas are considered to be "true" or "untrue", we must understand the related underlying beliefs about truth itself; what I believe to be true is in part based on what I think truth itself actually is and how I can or cannot arrive at it.
General beliefs about truth can be broken down by ontology and epistemology:
Ontology: Branch of metaphysics concerned with identifying, in the most general terms, the kinds of things that actually exist. Thus, the "ontological commitments" of a philosophical position include both its explicit assertions and its implicit presuppositions about the existence of entities, substances, or beings of particular kinds. http://www.philosophypages.com/dy/o.htm#ontg
Basically, an ontology is an underlying assumption about what the actual nature of existence, matter, Truth is: what is existence? What are things made out of...for example, is there a human spirit or is the human mind simply organic and biological? Is there or isn't there a Supreme Being or deity, and if there is, what is its nature? Etc etc.
All conclusions or arguments or even ideas about anything have implicit ontologies: all ideas imply a philosophy about the nature of "truth".
In this class, we'll mainly deal with the difference between scientific/empirical ontologies and faith-based or religious ontologies. We'll also think a wee bit about legal and medical ontologies.
Epistemology: the theory of knowledge, is that branch of philosophy concerned with the nature of knowledge, its possibility, scope, and general basis. This is obviously very closely related to ontology, but think of epistemology as a philosophy about how we come to know the truth: the method. So, science has an ontology: premises or philosophies about the nature of things, and science has an epistemology: premises or philosophies about how those or that "truth" is revealed to human beings. The same goes for religions, and legal systems, and medicine etc.
Here's why these big philosophical questions help us frame both valid and persuasive arguments:
Premise: All persuasion revolves around a negotiation of "truth"; the art of persuasion (rhetoric) is essentially the art of one party convincing another party to adopt the first party's version of truth.
(Note: "truth" can be a matter of what something truly is, what something truly was, what something probably can be, or what someone should do. In this way, "truth" intersects with arguments of belief (fact and values) and action.)
Premise: All ideas -- the contents of every thought in every person's mind -- has a history; at some point, we were somehow persuaded to believe whatever it is we believe, about anything. This is as true of the big beliefs -- "We hold these truths to be self evident, that all men are created equal...." -- as it is of our small beliefs -- "People in Minnesota will not buy roach killer" "Dams should be removed." "Dams should not be removed." "Saddam has wmds." Saddam does not." "there is a god; there is no god etc."-- and everything in between.
The history of any given idea is both personal -- how I personally came to believe it -- and cultural -- how/why the culture came to believe it and why/how it passes it on.
Note: this is as true of valid beliefs as it is of invalid ones.
Premise: Although some beliefs are based on first hand experience (the basis of Empirical thinking), the vast majority of all beliefs are based on "second hand experience" (the Lines of Argument): people are persuaded to believe ideas based on what they are told about those ideas through our exposure to culture: family, schools, churches, media etc.
Premise: Parties are persuaded based on the lines of argument: ethos, pathos, logos and appeals to values. The lines of argument can be used, therefore, in part to explain the history of the idea; therefore, understanding the person or the culture helps us understand the idea, and conversely understanding the idea helps us understand the person or culture.
Premise: In terms of logos, we must understand not only the logic and evidence but what people believe to be valid logic and evidence.
Premise: In terms of belief, there is no universal, objective truth, nor universal appeal to a universal lines of argument; different people understand or believe different things to be true and value different types of appeals to the lines of argument. Simply put: in any given argument, there is no single, universal rhetorical strategy that will convince all possible audiences.
Note: this is an entirely separate statement than "there is no universal, objective truth"; there might be a single, objective "truth", but obviously we don't all agree on what it is.
Therefore, We Can Conclude that understanding the ontology and epistemology of an idea, and the ontological and epistemic relationship your audience has to that idea is central to the art of persuasion.
So, putting this all together, in order to persuade someone:
We must understand WHY our audience believes something is true, and to do so, we must understand:
What they currently understand about the idea. What they believe about that idea.
How they were persuaded to believe what they currently believe; the process used to develop those beliefs: their relationship to a given Lines of Argument in relation to the idea; what they value, who they trusted and who they are willing to trust, what sorts of emotional appeals moved them toward adopting the belief.
Their relationship to "truth" (nature of knowledge and being) in general; what you think truth is to begin with: the underlying ontology and epistemology of the idea itself.
In the very simplest terms, if the audience's belief is based on faith, all the scientific reasoning in the world will never persuade them to change their mind, and vice versa. So understanding the ontology and epistemology of a belief is really essential to changing it...and changing existing beliefs is the basic purpose of all persuasion.