One interesting question that comes up with the pragmatic theory of truth is how to usefully incorporate it in our day to day thinking (and if we even should do this.) After all, in our day to day thinking and interaction with our experiences, we tend to assume many things that are completely unprovable. Here is a short list of some of these things:
- We assume that our experiences are actually what is "out there", outside of ourselves. In reality, it is not possible to know this one way or the other.
- We assume that other people (and to some degree, animals) are conscious creatures very much like us and with a similar internal experience. While this explanation makes sense (other people act much like us, so it makes sense that they are internally similar), it is not yet provable in any direct, logical way.
- We assume that our own mental experiences are all connected as part of a single whole called the "self." We intuitively separate our sensory experience from this concept of "self", but there is no logical line to draw between sensory experiences and mental experiences; sensory experience is a class of mental experience.
- We assume that some observed events "cause" other events. We believe that there is a metaphysical link between certain events that correlate with one another, but not other events that correlate with one another, even though we can never observe this link.
- We assume the future will be like the past. We assume that, because the sun came up the last 10,000 days we've been alive, it will come up tomorrow. We construct most of our theories about the world based on this unprovable assumption.
The evolutionary explanation is simple; the above assumptions are simple (meaning that they take little time and energy to grasp) and get the job done, at least when it comes to surviving and reproducing. There is no evolutionary advantage to making a distinction between experience and the world outside of experience, or to questioning whether other human beings are also conscious creatures with internal mental experience.
It is useful, I think, to simply not fight these assumptions in day to day living and discourse. They are useful and there really is no advantage to questioning whether you and I are looking at the same sky, or whether you can think about things like I do, when I am talking to you about the sky.
Of course, this brings up the question; what is the use of pragmatism to anyone but philosophers? Why even bother to have pragmatism; why not simply assume the correspondence theory of truth and live that way in all situations?
I think that there are psychological benefits to being aware of the pragmatic theory of truth on an abstract level even if it can't be fully integrated. First, it gives us more clarity when comparing competing theories (both scientific and otherwise). We are in a better position to determine which theory is better and why since we now understand what makes a theory good or bad.
Secondly, I think it gives many benefits towards understanding other people (after, of course, accepting the assumption that other people are conscious beings like ourselves). Deep down, everyone is a pragmatist. Even someone who is philosophically defending, say, the correspondence theory of truth has pragmatic reasons for doing so. He finds the theory useful in some way for coming to grips with his experience (which he calls "the world") and is drawn to it for that reason.
It really puts to rest the notion that truth is ever valued for its own sake, or that beliefs are not attached to utility. This has the potential to sharply improve our understanding of why people do the things they do and believe the things they believe.
Thirdly, I think it improves our understanding of ourselves. Once you accept that you believe the things that you believe, not due to some noble commitment to truth, but because those beliefs are useful to you, you are now in a position to ask yourself why you believe what you believe and get real answers. This also improves our ability to empathize with people that disagree with us; they are self-interested creatures drawn to certain ideas because it improves their lives, just like we are.
(2) Future, Past, and Evolution
An interesting point is that, for natural selection to have resulted in animals like us that assume the future will be like the past, the future only has to have been like the past up until this point. If the future were like the past right up until tomorrow, for example, we would still be the result of natural selection, but the metaphysics intrinsic to our thinking would shatter in pieces tomorrow and we would have no way to come to grips with our experience.