We Don’t Know What We Don’t Know

There is a widely quoted philosophical saying attributed to Socrates: “The only thing I know is that I know nothing.” Taken strictly at face value, it contains an obvious contradiction: if you know that you know nothing, you already know at least one thing, so you cannot claim to know nothing at all. Of course, these may not have been Socrates’ actual words. In Plato’s Apology, his point is closer to this: do not assume you know what you do not know. But even if we understand the saying as “I know that I do not know”, we can still ask a further question: to what extent can we know what we do not know?

We can readily acknowledge gaps in our knowledge once we become aware of them. Yet there are also things whose very existence has never occurred to us. We do not even know what essential knowledge or conditions are missing from our understanding. That is why I prefer to remind myself of another saying: “We don’t know what we don’t know.” It sounds a little convoluted, but it comes from observations accumulated over many years of everyday life, rather than from an exercise in wording alone.

People often find it difficult to take in other people’s views, especially when those views conflict with what they already believe. Someone’s advice may be simple, or it may draw on years of practical experience, yet the listener may dismiss it as wrong simply because they cannot understand it at the time. This response does not necessarily come from arrogance. We all need to make judgements using the knowledge, experience and reasoning abilities we already have; that is both normal and necessary. The difficulty is that, when those resources are themselves limited, we may use our limited capacity for judgement to reject sound advice that lies beyond our present understanding. The less experience we have in a particular area, the harder it can be to see why a piece of advice matters; and the less we understand it, the more readily we may reject it. Precisely because we do not know what we do not know, we lose the opportunity to acquire that knowledge.

Piano practice offers an example. Most people who learn the piano are familiar with Hanon exercises, which are mainly used to develop finger independence, agility, coordination and control of the keyboard. Opinions differ on whether players should consciously lift their fingers high when practising. Some beginners observe that professional pianists use very small, sometimes remarkably gentle finger movements when playing Chopin, and conclude that they should not deliberately lift their fingers when practising Hanon either. What they see in the performance is not wrong. What they may overlook is the distinction between technical training and actual performance.

Hanon provides training material, much as dancers stretch and practise leg kicks, or singers work on vocal exercises every day. Some movements used in practice aim to develop particular physical abilities; that does not mean they should be reproduced in the same way during a performance. For some beginners whose finger independence is underdeveloped and whose range of control is limited, a teacher may recommend consciously practising the lifting and lowering of the fingers while staying relaxed, gradually building their range of movement and control. This does not mean that higher is always better, or that one method suits everyone; excessive lifting can also create tension. The point here is that the purpose of a training exercise should not simply be conflated with the movements used in performance.

An experienced teacher may ask beginners to do things they do not yet understand because the teacher has seen the long-term effects of certain kinds of training and knows which approaches are likely to lead them astray. Beginners see that professional performers use small movements, but may not realise that those performers already possess the control that they themselves are still learning to acquire. Even without guidance, someone may eventually find the same approach through months, or longer, of trial and error. But having someone point out the key issue in advance may save a great deal of ineffective practice and experimentation. This is an important benefit of passing on experience: we do not have to repeat every detour that others have already taken.

There are countless similar situations in life. We encounter them when learning music or programming, working in technical fields, and dealing with everyday problems. When people are young in particular, they may have relatively little experience while feeling a strong urge to act and considerable confidence in their own judgement. This has to do with the psychological and physiological characteristics of that stage of life, as well as the extent of their accumulated knowledge and practical experience. Only years later, looking back, do they discover that some views they once held with complete confidence were unreliable. Some mistakes do need to be experienced first-hand before we can understand them, but many detours could have been avoided by listening carefully to people who had already been through them.

Acknowledging the limits of our own understanding, however, does not mean accepting everything other people say. Experienced people also make mistakes. Some merely repeat familiar practices without understanding whether those practices are reasonable, and professional credentials do not guarantee reliable judgement on every specific issue. Another ability is therefore needed: recognising people who actually possess the relevant knowledge, experience and judgement. Without that ability, even someone willing to learn with humility may learn the wrong things from the wrong people and be led astray.

Knowledge and experience are not evenly distributed. In a particular field, someone who has spent years studying and practising will usually know more than a beginner and will often be more likely to judge correctly. When a person with twenty years of relevant practical experience and someone just starting out offer different views on the same professional question, there is no reason to assume that the two are equally reliable. This is, of course, a judgement about probability; it does not mean that the expert must be right or the beginner must be wrong. Respecting this difference means respecting the actual distribution of knowledge and experience, rather than blindly submitting to authority.

How, then, can we recognise a real expert? Age, titles, seniority and confidence are not enough. We also need to consider whether the person has knowledge relevant to the particular question, can explain the grounds for their judgement, has a reliable record of practical results and past judgements, and is willing to revise their views when the facts change. There is a further difficulty: if we do not understand the field ourselves, how can we judge who does? There is no foolproof method, but we can at least examine their actual achievements, the way they argue, their long-term record, and how other trustworthy professionals assess their views. These assessments can still be mistaken, yet they have a firmer basis than deciding whether to accept advice solely by asking whether it fits what we already believe.

When identifying valuable advice, we also need to avoid a common mistake: listening only to the experience of successful people while readily dismissing the views of those who have failed. The successful people we see may simply be the survivors among many who tried; without knowing about those who used similar approaches but failed, we can easily mistake some of the things successful people did for generally effective principles. Moreover, a person’s success often occurs only under particular conditions and in particular fields, yet the life advice they offer on that basis may extend far beyond what those experiences can support. Conversely, having failed does not make someone’s views unworthy of consideration. If they can reflect carefully, draw lessons, understand the causes of their failure, and apply those insights successfully in later practice, then they know both which approaches do not work and how to adjust their methods. Their experience may be richer, and their advice more valuable. To judge whether a view is valuable, we need to look beyond whether the person offering it is a success or a failure and consider what they have learnt from their experience, whether those lessons are well founded, and the conditions under which they apply.

Listening carefully to someone’s advice does not mean immediately accepting their conclusion. When a person with relevant experience offers a view we cannot yet understand, we can suspend judgement, hear why they hold it, and then test it against evidence and practice. This neither abandons independent thought nor treats our present understanding as the final standard for judging everything. What we need to watch for is the unnoticed shift from “I don’t understand this” to “This must be wrong”.

Much popular online advice now tells people how to get along with others: do not be too quick to point out someone’s mistakes, for example, because it may bring little thanks or even be seen as a sign of low emotional intelligence. There are practical reasons for such advice, but it can also create a closed loop in which people become increasingly reluctant to offer well-intentioned warnings and find it increasingly difficult to receive help from others. Pointing out a mistake is not necessarily an attempt to show off; it may come from goodwill and a sense of responsibility. If we make avoiding offence a general principle, we may preserve surface harmony while losing opportunities to correct mistakes, learn from one another and make progress together.

We usually understand rationality as the ability to analyse and judge independently, but it should also include an awareness of its own limits. If we reject everything we cannot yet understand, the knowledge we already have may become an obstacle to acquiring new knowledge. If, on the other hand, we give up making judgements and let others decide for us because we know our understanding is limited, we lose rationality just as surely. A more reasonable approach is to retain our capacity for judgement while leaving room for views we do not yet understand but have good reason to take seriously. “We don’t know what we don’t know” is, first of all, something to say to ourselves. It reminds us that our understanding may always contain blind spots we have not yet discovered, and that other people’s experience and knowledge sometimes give us the opportunity to find them.