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On Certainty

4.16  ·  Rating details ·  3,576 Ratings  ·  78 Reviews

Written over the last 18 months of his life and inspired by his interest in G. E. Moore's defence of common sense, this much discussed volume collects Wittgenstein's reflections on knowledge and certainty, on what it is to know a proposition for sure.

Hardcover, 90 pages
Published December 31st 1969 by Blackwell Publishers (first published 1969)
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Some interesting things that people are certain about:


You have an invisible friend who is the most important being in the world and responsible for everything that happens.


The great strength of science is that all its findings are provisional and subject to revision at any moment if new evidence comes in. This is why you should trust it.


Even 0.1% growth over a few tens of millenia would result in an economy bigger than the known universe. But, although it is impossible
David Katzman
Feb 03, 2009 rated it really liked it  ·  review of another edition
I’m not…certain how I feel about this book. What I mean more precisely is…that…it is impossible for me to be certain how I feel about this book. In fact, it’s impossible for me to really be certain of anything whatsoever. According to Mr. Ludvig Vittgen-shhhhhhhtein, that is.

On Certainty was a rather enjoyable read despite the fact that it contained 676 numbered paragraphs of somewhat repetitive analysis. But if one is as fascinated by philosophy as I am, then it’s no bother. Some would say Witt
Aug 15, 2013 rated it really liked it  ·  review of another edition
I will not be able to use "I know" in my vocabulary without first questioning my statement's certainty a hundred times. Would I be certain of my knowledge then? I might not be. Wittgenstein, in this book, uses short philosophical and linguistic reflections on "knowing" as a response to G. E. Moore's 1939 paper, “Proof of an External World”. He asks you to emphasize on "I believe" than "I know" whenever you "don't know", because when you think you "believe", and say that you "know", you actually ...more
William West
It seems to me that Wittgenstein is trying, with this very late work, to answer the questions raised in his Tractatus in the terminology he employed in his mid-period, that of the language games of the Blue and Brown Books and Philosophical Investigations. With On Certainty, finished two days before the author's death, I think Wittgenstein arrives at surprisingly Kantian conclusions.

Wittgenstein begins both this work and the Tractatus with an inquiry into that of which he can be certain. In the
Oct 27, 2007 rated it it was amazing  ·  review of another edition
Recommends it for: Sully
Shelves: philosophy
Strange, wonderful little book. It has its dull moments, but there are moments of blazing light.

How certain am I, that I have never been to Jupiter?
"It is as certain as any grounds I could give for it."
Apr 18, 2010 rated it really liked it  ·  review of another edition
What can we be certain of? The only thing Wittgenstein is certain of is that there's something fishy about philosopher G.E. Moore's assertions "I know that that's a tree" or "I know that here is a hand" or "I know that I have never been far above the earth's surface." Wittgenstein is terribly perturbed by these statements but doesn't know quite why. It has something to do with the fact that the only people who ever make such statements are philosophers; the rest of us "know" such things by simpl ...more
Jun 06, 2011 rated it it was amazing  ·  review of another edition
Shelves: philosophy
Wittgenstein always fascinates me. He is not easy to read unless you are willing to go into his terrain of mind. He has a different mind from most of us, above, on a meta level of what we call "things in life". This book questions all the things we take for granted in order to live, to the extreme extent of almost being silly. After the questioning, there is not much left to maintain the human life. I wonder how many people can overcome that void.
Theresa Macphail
Jan 19, 2011 rated it it was amazing  ·  review of another edition
Shelves: philosophy
I love Wittgenstein for, if nothing else, his pithy writing style. I also find him helpful for thinking through my research data in terms of the relationship between certainty, uncertainty, and the production of knowledge. Worth it, even if you haven't read Philosophical Investigations.
Jan 24, 2008 rated it it was amazing  ·  review of another edition
Recommends it for: skeptics
i couldn't decide whether this book is for humans or space aliens. i guess it's for both.

wonderful wittgenstein. 90 excruciating pages (676 numbered sections) on whether G. E. Moore was justified in holding up his hand and saying, "I know that here is my hand." the second half is quite creepy to read, as he was dying of cancer while writing it. the dates are on the entries, with the final page written two days before he died.

127 - how do i know that someone else uses the words "I do
Jan 08, 2015 rated it really liked it
Would it be extremely weird of me if I said it was a 'fun' read? As much as saying this amuses me, this was a really funny book, and I mean in a very positive and serious way. First thing Wittgenstein does to you, from the outset, is tear apart your cozy little way of thinking, and 'knowing'. I'll never 'know' anything the way I've known before, or at least I'll think a second more before I say I'm certain of something. Next, as you read and re-read and re-re-read almost every other sentence, yo ...more
Mar 13, 2014 rated it it was amazing  ·  review of another edition
This was an excellent read. Wittgenstein's main works are, of course, the Tractatus and Philosophical Investigations, but some consider On Certainty to be his third major work. Unfortunately, On Certainty was not formally organized by Wittgenstein. It is more or less a collection of notes, which represent Wittgensteinian thought post-PI.

Some readers take Wittgenstein's stance in these notes to be sceptical. I personally don't sympathize with this view. If anything, Wittgenstein is starkly anti-s
Erik Graff
Mar 05, 2009 rated it really liked it  ·  review of another edition
Recommends it for: Wittgenstein fans
Recommended to Erik by: Bill Ellos
Shelves: philosophy
As recalled, this was my favorite volume of the very many produced by the clever fellows who have made careers out of his. Wittgenstein himself published very little, but an enormous body of works attributed to him have been culled from his correspondences, notebooks and students' notes of lectures and conversations.

On Certainty comes as close as Wittgenstein ever does to being a systematic philosopher rather than just playing at being a skeptic, phenomenologist, speculator or analyst of languag
Olli K
Feb 16, 2010 rated it really liked it  ·  review of another edition
I read Tractatus Logico Philosophicus and On Certainty one after another and I must say that On Certainty is much more enjoyable to read than TLP. At least if you do not have any previous knowledge about philosophy.

I was happy to notice that this book was not so hard to read and gave the reader opportunity to form own opinions. At one point I even noticed that there was a flaw in Wittgenstein's thinking.

If you do not have any or very limited previous knowledge about philosophy and wish to read
David Williamson
I know I liked On Certainty, but that would be playing the language game properly, and not making a statement of fact, of this I can be certain but not know, of which I can be wrong but still believe...

This book sometimes feel like its a head on collision between philosophy and the everyday. What we can say and its implications within varied contexts, contexts that can never be nailed down. It's almost like what it would be like if an AI computer had a mental breakdown. Good stuff.
Aasem Bakhshi
Mar 06, 2013 rated it really liked it  ·  review of another edition
Shelves: philosophy
At times tough, at times perplexing, at times dull. Its about language, not epistemology but kind of vague epistemic conjecture in undertones. Looks like a soliloquy but a wonderful little masterpiece.
Michael Starks
Sep 02, 2012 rated it it was amazing  ·  review of another edition
Recommends it for: everyone
Recommended to Michael by: nobody
On Certainty was not published until 1969, 18 years after Wittgenstein’s death and has only recently begun to draw serious attention. I cannot recall a single reference to it in all of Searle and one see’s whole books on W with barely a mention. There are however xlnt books on it by Stroll, Svensson, McGinn and others and parts of many other books and articles, but hands down the best is that of Daniele Moyal-Sharrock (DMS) whose 2004 volume “Understanding Wittgenstein’s On Certainty” is mandato ...more
Aug 06, 2015 rated it really liked it  ·  review of another edition

This is a slim little book that Wittgenstein wrote toward the end of his life, in his characteristic numbered succinct paragraphs. It's good. Clear, somewhat repetitive (though that's only a plus because you never know when you're missing something in his hyper-compact writing), it tackles the perennial questions of uber-skepticism: can you doubt everything, even the existence of the world and my body?

Does the world exist?

The book was actually written in response to G.E. Moore's landmark
Brandon Henke
Epistemology as linguistic analysis. The phrase "I know _" is more appropriately rephrased as "I believe _ to be so", that is, an expression of a degree of certainty regarding a proposition that is dependent on a specific frame of reference. That all judgments of "truth" ultimately rely on some faithful assumption is an important insight. And yet, I'd much rather read about the domain-specificity of skepticism and heuristics à la Nassim Taleb than proceed further down Wittgenstein's rabbit hole ...more
Oct 12, 2013 rated it liked it  ·  review of another edition
Shelves: philosophy
Do we become more or less certain as we get closer to death? In Wittgenstein's case, judging from his notes during his final days, he was open to questioning even the most obvious and trivial facts. The book was published posthumously from notes compiled within his last two years alive in the early 1950s, and did not appear to a broader audience until nearly 20 years after his death.

The text was written mostly, but not exclusively in German. I benefited from having the German and English side-b
Mohammad amin
ويتگنشتاين را در قم خواندم. يعني در تمام مدتي كه از ظلمت شب (با اتوبوس) به سمت طلعت سحر در تحرك بودم.
در قم بيشتر در باب يقين ويتگنشتاين غور كردم.
ويتگنشتاين آن چيزي نبود كه تصور ميكردم. بعدها سه كتاب از او را خواندم.
در باب يقين او حاصل دو سه سال آخر عمر اوست كه بعدها عليالظاهر جمع و نشر شده.
دو وجهه متفاوت از او برداشت كردم.
يك. ويتگنشتاين در خدمت تجدد
دو. ويتگنشتاين در خيانت به تجدد.

دوستانم معتقد به گزينهي دوم هستند. اما من ويتگنشتاين را ادامه مدرنيته و در خدمت جهان متجدد فهميدهام. البته فعلاً.
Algirdas Brukštus
Wittgensteinas - tai lyg švitrinis popierius racionalumo skalpeliui šveisti.
Sep 24, 2011 rated it it was amazing  ·  review of another edition
Amazing. Wittgenstein goes in circles a bit trying to get across his point (then again, these are his notes/journal), but this ranks among my favorite books of all time.
Jun 18, 2008 is currently reading it  ·  review of another edition
More Wittgenstein!
David F.
Wittgenstein’s On Certainty was written as a response to G. E. Moore's 1939 paper, “Proof of an External World.” In this paper, Moore applies what is known as the Moorean shift from modus ponens (if A then B; A, therefore B) to modus tollens (if A then B; not-A, therefore not-B). In particular, Moore offered as proof that there is a world external to our senses (a not-B in this case) by the act of holding up his hand and saying “here is a hand” (a not-A in this case). While Wittgenstein is clear ...more
Philip Cartwright
As the title suggests, On Certainty is a sustained meditation on the philosophical problems surrounding concepts such as “certainty”, “knowledge” and “belief”. Unlike Philosophical Investigations, which Wittgenstein spent several years obsessively polishing and refining (though it was never actually finished), On Certainty is first-draft material jotted down over the last eighteen months of his life. As such it is both fascinating and frustrating to read. Fascinating because of the insights it c ...more
Aug 09, 2011 rated it it was amazing  ·  review of another edition
Really interesting book. A diary of Wittgenstein's thoughts on a couple of Moore's pieces, on which the latter proved the obvious: "This is my hand," "That is a tree." The aphorisms add up to a complex analysis of thought, belief, knowledge, language games, forms of life, learning, doubt, and what is a mistake is. The basic argument is that for Moore his hand really is certainly his hand, yet Moore's knowledge is not really anything more than his firm conviction in his own belief. All knowledge ...more
Sep 26, 2007 rated it it was amazing  ·  review of another edition
I don't much care for the format: the book consists simply of 600-700 numbered aphorisms, or in some cases simply statements, of Wittgenstein's. There is no real structure, though certain statements follow from those which preceded them.

That said, the numbered statements are really interesting and sometimes quite odd while quite logical. Also, as a beginning German student, it's wonderful to have short statements like this in a bilingual edition. Many words are used over and over again, and it p
Sep 12, 2007 rated it it was amazing  ·  review of another edition
As a Philosophy undergrad, Wittgenstein's writing was refreshingly plain-spoken. So much Modern Western philosophy is poorly written, so much philosophy is poorly written. Which is frustrating because the point is to clearly present some idea.

Anyway, Wittgenstein's numbered series of questions and remarks strikes me as a more appropriate way to render philosophical ideas -- more appropriate than the grammatically confusing literature of all those Modern Western giants. W's writing seems less im
Dec 14, 2015 rated it really liked it  ·  review of another edition
This book belongs to the last 1 1/2 years of Wittgenstein's life. In 1949, he visited the US at the invitation of Norman Malcolm and stayed at his home in Ithaca, NY. Malcolm goaded Wittgenstein to write about G. E. Moore's famous "defence of common sense." Moore claimed to know a number of propositions for sure. For example, Moore stated in "Proof of the External World" the following:

"Here is one hand, and here is another."

That quote by the way explains the cover with hands on it.

Here are tw
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Ludwig Josef Johann Wittgenstein (26 April 1889 – 29 April 1951) was an Austrian-British philosopher who worked primarily in logic, the philosophy of mathematics, the philosophy of mind, and the philosophy of language.

Described by Bertrand Russell as "the most perfect example I have ever known of genius as traditionally conceived, passionate, profound, intense, and dominating", he helped inspire t
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“I am sitting with a philosopher in the garden; he says again and again 'I know that that’s a tree', pointing to a tree that is near us. Someone else arrives and hears this, and I tell him: 'This fellow isn’t insane. We are only doing philosophy.” 185 likes
“I act with complete certainty. But this certainty is my own.” 89 likes
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