In my last semester I visited a seminar in which we discussed Quassim Cassam’s book Self-Knowledge for Humans. It was concerned with the sources and the epistemic standing of different kinds of self-knowledge as well as the way we are able to acquire it.
It is always funny to see how the interests of academic philosophers and everyday thinkers vary and the distinction between trivial and substantial self-knowledge is a good example for that.
a) trivial self-knowledge describes the sort of second order knowledge (the knowledge of ones mental states like beliefs and desires) about oneself that is concerned with very simple things in life. I know that I believe that I am wearing beautifully colored striped socks, I know that I prefer chocolate ice cream over vanilla flavored ice cream, I know that I think that David Bowie was the most amazing musician ever.
b) substantial self-knowledge on the other hand concerns knowledge about my own character, about my values, my aptitudes, etc.
Cassam is right in pointing out that most academic philosophers that discuss the issue of self-knowledge focus on the first type while most other people probably feel like the the second type is of much more importance. Who would write passages, pages, or even books about their knowledge of their beliefs about socks (even if they are really pretty looking)?
The answer to the discrepancy can be found when we look at the thinkers’ goals.
Philosophers that are mainly interested in questions concerning epistemology (~what can we know? What is knowledge? How could and should we increase our own knowledge? And countless more questions) are interested in the type of knowledge that seems to have a special epistemic standing. Trivial self-knowledge can easily be gained. It seems to be an automatic process and we are unlikely to err in these cases. Immediacy* would be the first property that makes it special. Incorrigibility is the second one. When it comes to my knowledge of my food preferences I am in the best position to actually give a correct answer. It would seem weird if another person came along to tell me that I actually like the taste of vanilla ice cream the most. Finding out about those distinctions is important as it helps us gain important conceptual tools when it comes to understanding how we learn about our inner lives and how secure the types of knowledge are (this gains special importance in the context of the question of epistemic authority (the question of whose beliefs should be rationally accepted).
Substantial self-knowledge is neither immediate nor incorrigible so it lacks a special epistemic standing and is therefore not as interesting for many academic philosophers. Most everyday thinkers seek solutions to important and difficult questions about themselves which automatically leads them to the second type of self-knowledge. They want to gain an insight into their own character and try to learn what drives or scares them. They try to learn who they are and who they want to be and the knowledge they acquire is difficult to gain. It is also not only possible, but quite likely that we (as humans with our specific psychological condition) make mistakes in the self-attribution of certain values and in many instances it is possible that a close friend, family member, or partner is in a better position to judge certain character traits than we are.
The abstract about trivial self-knowledge was supposed to illustrate the peculiar way of viewing a certain topic from a perspective of contemporary theoretical philosophy. What this second part teaches everyone of us is that in some instances, we should not immediately assume that we know a certain aspect of our personality the best. Learning about oneself is not only an individual, but also a social process. We can (partly) get to know ourselves through others.
*In the course of the book Cassam also rejects the immediacy of trivial self-knowledge, but the immediacy assumption remains important, because it is endorsed by many rationalist thinkers.
Cassam, Quassim: Self-Knowledge for Humans. Oxford, 2014.