Most of the time, most of us are convinced that we know far more than we are entitled to, even by our own commonsensical notions of what real knowledge is. There are good reasons for this, and let me hasten to say I do it too.

I’m not just referring to things we think we know that turn out to be wrong. In fact, let’s restrict our attention initially to those bits of knowledge we claim for ourselves that turn out to be true. If I say “I know that X is the case” and X really is the case, then why might I still be making a mistaken claim?

To begin with, I might claim I know X is the case because I got that message from a source I trust. Indeed, the vast majority of what we usually consider “knowledge” isn’t even second-hand. It really is just third-hand or even further removed from direct experience. Most of what we think we know not only is just stuff we’ve been told by someone, it’s stuff we’ve been told by someone who in turn was told it by someone else who in turn… I sometimes ask classrooms of students how many of them know the Earth is round. Almost all hands go up. I then ask how many of them could prove it, or offer a reasonable argument in its favor that would pass even a mild skeptic’s scrutiny. Very few (usually no) hands go up.

The same problem for our knowledge-claims crops up if we venture onto riskier taboo-ridden ground, such as whether we really know who our biological parents are. As I’ve described in an earlier post, whenever obtaining first-hand knowledge is costly or risky, we’re compelled to take second- or third-hand information on faith or trust. I’ve also mentioned in an earlier post our capacity for vicarious learning; to this we can add our enormous capacity for absorbing information from others’ accounts (including other’s accounts of others’ accounts…). As a species, we are extremely well set-up to take on second- and third-hand information and convert it into “knowledge.”

The difference, roughly speaking, is between asserting a belief and backing it up with supporting evidence or arguments, or at least first-hand experience. Classic social constructivism begins with the observation that most of what we think we know is “constructed” in the sense of being fed to us via parents, schools, the media, and so on. This line of argument can be pushed quite far, depending on the assumptions one is willing to entertain. A radical skeptic can argue that even so straightforward a first-hand operation as measuring the length of a straight line relies on culturally specific conventions about what “measurement,” “length,” “straight,” and “line” mean.

A second important sense in which our claims to know things are overblown arises from our propensity to fill in the blanks, both in recalling past events and interpreting current ones. A friend gestures to a bowl of food he’s eating and says, “This stuff is hot.” If we’re at table in an Indian restaurant eating curries, I’ll fill in the blank by inferring that he means chilli-hot or spicy. On the other hand if we’re in a Russian restaurant devouring plates of piroshki, I’ll infer that he means high temperature. In either situation I’ll think I know what my friend means but, strictly speaking, I don’t. A huge amount of what we think of as understanding in communication of nearly every kind relies on inferences and interpretations of this kind. Memory is similarly “reconstructive,” filling in the blanks amid the fragments of genuine recollections to generate an account that sounds plausible and coherent.

Hindsight bias is a related problem. Briefly, this is a tendency to over-estimate the extent to which we “knew it all along” when a prediction comes true. The typical psychological experiment demonstrating this finds that subjects recall their confidence in their prediction of an event as being greater if the event occurs than if it doesn’t. An accessible recent article by Paul Goodwin points out that an additional downside to hindsight bias is that it can make us over-confident about our predictive abilities.

Even a dyed-in-the-wool realist can reasonably wonder why so much of what we think we know is indirect, unsupported by evidence, and/or inferred. Aside from balm for our egos, what do we get out of our unrealistically inflated view of our own knowledge? One persuasive, if obvious, argument is that if we couldn’t act on our storehouse of indirect knowledge we’d be paralyzed with indecision. Real-time decision making in everyday life requires fairly prompt responses and we can ill afford to defer many of those decisions on grounds of less than perfect understanding. There is Oliver Heaviside’s famous declaration, “I do not refuse my dinner simply because I do not understand the process of digestion.”

Another argument invites us to consider being condemned to an endlessly costly effort to replace our indirect knowledge with first-hand counterparts or the requisite supporting evidence and/or arguments. A third reason is that communication would become nearly impossibly cumbersome, with everyone treating all messages “literally” and demanding full definitions and explications of each word or phrase.

Perhaps the most unsettling domain where we mislead ourselves about how much we know is the workings of our own minds. Introspection has a chequered history in psychology and a majority of cognitive psychologists these days would hold it to be an invalid and unreliable source of data on mental processes. The classic modern paper in this vein is Robert Nisbett and Timothy Wilson’s 1977 work, in which they concluded that people often are unable to accurately report even the existence of their responses evoked by stimuli or that a cognitive process has occurred. Even when they are aware of both the stimuli and the cognitive process evoked thereby, they may be inaccurate about the effect the former had on the latter.

What are we doing instead of genuine introspection? First, we use our own intuitive causal theories to fill in the blanks. Asked why I’m in a good mood today, I riffle through recent memories searching for plausible causes rather than recalling the actual cause-effect sequence that put me in a good mood. Second, we use our own folk psychological theories about how the mind works, which provide us with plausible accounts of our cognitive processes.

Wilson and Nisbett realized that there are powerful motivations for our unawareness of our unawareness:

“It is naturally preferable, from the standpoint of prediction and subjective feelings of control, to believe that we have such access. It is frightening to believe that one has no more certain knowledge of the workings of one’s own mind than would an outsider with intimate knowledge of one’s history and of the stimuli present at the time the cognitive process occurred.”

Because self-reports about mental processes and their outcomes are bread and butter in much psychological research, it should come as no surprise that debates about introspection have continued in the discipline to the present day. One of the richest recent contributions to these debates is the collaboration between psychologist Russell Hurlburt and philosopher Eric Schwitzgebel, resulting in their 2007 book, “Describing Inner Experience? Proponent Meets Skeptic.”

Hurlburt is the inventor and proponent of Descriptive Experience Sampling (DES), a method of gathering introspective data that attempts to circumvent the usual pitfalls when people are asked to introspect. In DES, a beeper goes off at random intervals signaling the subject to pay attention to their “inner experience” at the moment of the beep. The subject then writes a brief description of this experience. Later, the subject is interviewed by a trained DES researcher, with the goal of enabling the subject to produce an accurate and unbiased description, so far as that is possible. The process continues over several sessions, to enable the researcher to gain some generalizable information about the subject’s typical introspective dispositions and experiences.

Schwitzgebel is, of course, the skeptic in the piece, having written extensively about the limitations and perils of introspection. He describes five main reasons for his skepticism about DES.

Many conscious states are fleeting and unstable. Most of us have no great experience or training in introspection; and even Hurlburt allows that subjects have to be trained to some extent during the early DES sessions. Both our interest and available stimuli are external to us, so we don’t have a large storehouse of evidence or descriptors for inner experiences. Consequently, we have to adapt descriptors of external matters to describing inner ones, often resulting in confusion. Introspection requires focused attention on conscious experience which in turn alters that experience. If we’re being asked to recall an inner experience then we must rely on memory, with its well-known shortcomings and reconstructive proclivities. Interpretation and theorizing are required for introspection. Schwitzgebel concludes that introspection may be adequate for gross categorizations of conscious experiences or states, but not for describing higher cognitive or emotive processes.

Their book has stimulated further debate, culminating in a recent special issue of the Journal of Consciousness Studies, whose contents have been listed in the March 3rd (2011) post on Schwitzgebel’s blog, The Splintered Mind. The articles therein make fascinating reading, along with Hurlburt’s and Schwitzgebel’s rejoinders and (to some extent) reformulations of their respective positions. Nevertheless, the state of play remains that we know a lot less about our inner selves than we’d like to.