A reasoned belief is one that is founded on empiricism and a logical argument. Hopefully, we’ll all agree that logic is sound. If you argue that logic doesn’t work, then there’s no point in discussing anything at all with you, because no chain of reasoning can—well, reasoning depends precisely on logic! Thus, I will presuppose that we agree on logic, though you may or may not agree that empiricism is necessary, and some would even claim that empiricism is not epistemologically sound.
First, let me define what I mean by
empiricism (I am no philosopher; there may be more precise terms). I do not mean that what I see is necessarily reality (au contraire, I am well aware that our senses are flawed and our brains are prone to certain types of delusion). What I mean by empiricism is simply the following assumption: There exists a systematic relationship between external reality and the percepts of a healthy brain. I must define the brain as healthy: If it is not, it may not follow logic, and it may be plagued by hallucinations to the point where it cannot follow any sort of external reality. If so, alas, I posit that this brain is beyond help. It is not, I admit, impossible that this applies to any given brain, including my own; but absent evidence to this fact, it cannot serve me to believe it or to behave as though it were true, so I will assume that the percepts in my brain do systematically reflect an external reality. I do not, however, need to assume that the relationship is perfect—strictly speaking, all I need is statistical significance.
If I am allowed to assume both logic and empiricism (in the sense above), I can build up a consistent and coherent world view. It doesn’t matter (in principle) that the system is noisy—that some of my logic will be faulty and some of my perceptions incorrect. The assumptions suffice to formulate experiments, which allow me to verify my logic against observed reality, and cross-check my perceptions as much as I want. Repeated experiment lets me overcome the effects of noise in both argument and perception.
I will even take a controversial step and claim that logic needs empiricism for validation—the two cannot be extricated from each other. You cannot, after all, use logic to prove that logic is true—it’s circular (it only works if logic is true to begin with). If you are mathematically inclined, you may note that logic can be represented as a form of mathematics—I wonder if perhaps Gödel’s Incompleteness Theorem can provide a formal version of this verbal argument?
In any case, empiricism supports logic. The reason is as follows: If you assume both empiricism and logic, you can formulate experiments so that, given percept A, you can make a statistical expectation on percept B. This, however, presupposes logic. If we don’t have logic, we have no reason at all to suppose that B will follow A with any degree of certainty. Because we can empirically observe that experiments do bear out, this supports the logical reasoning that we used to make the predictions.
Of course this is far from iron-clad (and even in its weak form does also presuppose logic), but then we can’t really expect too much of an argument that tries to provide evidence for logic itself, now can we?
Having explained why I think that empiricism is a necessary assumption to make any sense of the world whatsoever, I suppose I should mention—however briefly—why I dismiss alternatives. The most obvious alternative is solipsism, the notion that none of the external world has any reality to it and all you can really know is your own mind. That’s not exactly nonsensical, but it’s not worth considering because it tells you nothing—it won’t get you anywhere. It provides no epistemological framework useful for interacting with anything (if everything you interact with is in your own head, why expect it to behave systematically?). It provides no reason to take logic seriously. It allows you no conclusions.
And, quite frankly, I think that all systems that reject empiricism and scientific thinking suffer of different degrees of the exact same thing. What you claim to
intuitively know I may very well
intuitively doubt, and if we are to settle it independently—well, we need logic and empiricism. If you claim that reality is somehow subjective and depends on your point of view, that your reality is not necessarily the same as mine, we lack a framework to interact, and it is self-defeating because you have no standing to declare that my view of reality as objective isn’t right (if you do so declare, you are making a distinctly universal and objective claim).
A logical argument, in its most basic form, looks like A⇒B; A; ∴B. In English: “If A is true, then B must be true; A is true; therefore B is true.” A and B are both
- You believe in proposition B without any logical or empirical reason. This is just silly.
- Your premise is correct (A really is true), but your argument is not
valid—A doesn’t necessarily imply B.
- Your argument is valid, but not
sound: Your premise, A, is not actually true.
- Your premise is false and your argument is invalid.
Note that it is quite possible to go from false premises to a true conclusion, or true premises to a true conclusion via an invalid argument. Reaching a correct conclusion is not proof of sound thinking!
The point of this discussion is that if once you believe in a set of premises and in a conclusion, it’s pretty easy to overlook flaws in the inference. If I know I believe B because A is true, and nothing occurs to gainsay either A or B, I’m not likely to revisit the inference A⇒B with a very critical gaze, because clearly, it worked. However, this is not a reasonable thing to do if this argument is my only reason for believing in B—and since I may have made a mistake in any argument, I should try to be critical of all of them (it may not be my only reason for believing something, but the other reasons may be unsound arguments, so I should treat each one as important). To me, critical thinking lies in scrutinising the premises, but especially of watching inferences very carefully. I pay less attention to conclusions (in a debate, I am unlikely to attack them), because they will flow naturally from the argument if once a sound argument is established.