How much don’t I know?
Are you aware of, or can you perceive, the volume of knowledge in the universe that you do not presently have?
It’s a simple question, do you know how little you really know?…
I don’t! It’s a simple question with a simple answer: it’s impossible to truly know how little you know, but we can speculate right?
So — why not join me on my cursory journey to speculate as to how little I really know?
- Is knowledge even quantifiable? Is it even possible to use numbers to analyse knowledge? Probably not! I’ll try anyway… But it’s a very crude representation.
- Of necessity any analysis into what I don’t know must be a mere glimpse, because I simply don’t know what I don’t know. So what is likely going to happen here is I am going to discuss the first atom on the tip of the iceberg of what I don’t know!
In this article I will merely give “glimpses” into certain random areas where I can actually find some concrete numbers to illustrate how little I know. OK? Here we go!
How little do I know?
Glimpse #1: my mother tongue
If someone were to ask me “do you speak English?” — well, the logical answer would be “yes”, but what does that mean anyway? What does it mean to be able to “speak English”?
English is my mother tongue, it’s the language I use daily for work, study, recreation, life. But how much of English do I actually speak?
It’s pretty much impossible to get an exact number, but it is estimated that a college-educated native English speaker knows about 17 000 word families  — so to be generous, let’s say I know 17 000 word families. Word families can have more than one word in them (like “family” and “families” are two different words in the same word family), but I don’t know how many words are in the average word family! Let’s just say being generous I know about 20 000 words then. The second edition of the 20-volume Oxford English dictionary had 171 476 contemporary words (in modern use) and 47 156 obsolete words  — which again doesn’t mean that English has that many words — it’s just the closest measure we can use.
Quite simply, this means I know about 11% of modern English, and about 9% of “modern and obsolete” English (where they draw the line of “obsolete” — who knows). Yeah, I’ve spoken English my whole life, grown up in it, gotten educated it it, and I only speak about a tenth of it! To be fair, the frequency distribution of words works heavily in my favour!
Glimpse #2: world languages
Technically I am trilingual, but functionally I am really only bilingual. I speak English (about 20 000 words!) and Mandarin (about 2 000 words) — let’s be generous to me and say I speak two languages (even though I only speak 10% of one, and 1% of the other!).
How many languages are spoken in the world? Again, an impossible question to answer accurately. Even the process of drawing a line and saying “this is ONE language” is not clear. However there are estimates — one such says there are 6 500 spoken languages in the word today 
So, I “speak” 2 / 6500 of the languages of the world. Or 0.03% of the languages of the world. Just think about that number for a second. Imagine the dimensions and depths of wisdom, experience, knowledge, enlightenment, humour, etc. that are contained within that remaining 99.97% of the languages of the world that I don’t understand or speak. Man, I’m missing out on a lot of fun!
Glimpse #3: mankind’s collective knowledge
Again, “mankind’s collective knowledge” is something impossible to measure accurately, but we can butcher the truth with some wildly inaccurate way of measuring it again!
OK, this page shows all of the undergraduate units that my university offers. and this page shows all of the postgraduate units they offer. It makes sense that you use the units of a university as a VERY rough measure of the knowledge that “mankind” currently has at a more involved level.
In total these units add up to around ~2700 units and throughout my university education I have completed (up to now) 23 units.
So using this very inaccurate measurement, and assuming that I remember everything from all of those units (yeah right! I do recall my physics teacher saying once that we remember less than 4% of university lectures in the long term, I think he was being generous) — this would mean that I “have” about 0.85% of the knowledge of mandkind! Actually, I am going to come out here and say “yeah right” — I think it is likely to be more like one hundredth of that number.
Glimpse #4: Considering glimpse #3, how much does “mankind” actually know?
Again like all of the glimpses so far, it’s really impossible to answer the question with any reasonable degree of accuracy. So I am just going to give two “mini-glimpses” into this question.
“Mini-glimpse” 4.1: how much of the ocean have we explored?
“To date, we have explored less than five percent of the ocean”  — think about that. I hardly know anything about what wehave explored, and that’s less than 5% of the whole ocean. I would go home now if I weren’t already at home!
“Mini-glimpse” 4.2: how much of the universe are we even dealing with?
Ignoring for a second the fact that the universe is so ridiculously vast that we have no hope of ever exploring it all (To throw some numbers, the milky way has about 300 billion stars  , and the universe has over 100 billion galaxies ) — let’s dive into something deeper, way way deeper.
What mankind has been living in, exploring, dying in, experiencing, and engaging with for it’s entire time here, is, in a word “matter” — your books, your TV, your body, your life, “matter” — and the numbers I just mentioned, 300 billion stars in a galaxy, and over 100 billion galaxies — you guessed it, all matter.
Matter — those numbers — that’s about 4.6% of the observable universe, where “dark matter” is about 23%, and dark energy is about 73%. Without going into detail of what those are, we don’t understand them much, we just know they are there based on measurements we’ve taken.
So herein I ask the question, “how much of the universe are we even dealing with?” mankind’s existence, our knowledge base, everything we have ever experienced or learned or built or done, is merely a minute fraction of the 4.6% of the universe — and your knowledge and mine, is merely a minute fraction of the knowledge of mankind. Did I mention that we are starting to postulate that there may be a multiverse? 
So how little do I know?
I feel very humbled to bounce around numbers that I completely don’t understand….
…”unfathomable” is the word that comes to mind. I simply cannot fathom how much I don’t know. Ironic conclusion, not only can we not practically know how much we don’t know, we couldn’t even understand how much that is, even if the information were readily available!
After bouncing around all of those numbers, I still feel it would be an insult to the “universe” to say something like “I realise now that I only know 0.000000000000001% of the knowledge of the universe” — pitiful.
But to be fair to myself, my achievements, mankind, and its achievements, at least we don’t know nothing.
But almost nothing.
References (yes, they’re lazy, just URLs, but “reliable” sources… I think)
 Just Google it! “how many stars in a galaxy” Yay for Google knowledge graph