A Philosopher Every Programmer Should Know: Susanne K. Langer

You can construe the cogito as an argument:

P1 I think.

P2 If I think, then I exist

C1 I exist.

P1 and P2 are premises, C1 is derived.

The interesting point is that P1 is not arbitrary, in the sense that if one grasps it, then it is true.

That's a really interesting property for a claim to have - especially for a contingent claim to have (e.g. 2+2=4 is necessarily true, and so if one grasps it, trivially it is true, but that's not interesting in the same way).

Further, D thinks that if one grasps it, then one knows one grasps it, (and that it is true).

So for D we have a priori certain knowledge of a contingent claim.

If course, you can question 2, and some people have. Quine is one person to read on that.

Re 'what does it mean to exist' - what do you mean by that? Your criticism demonstrates some ignorance of Descartes, as Descartes makes substantive claims about the nature of his existence as revealed by the reasonining in Mediations. For example D would say he knows that he exists as a thinking subject - a substantive claim about his nature. He goes on to make lots of controversial claims about his nature (some of which get us to Cartesian Dualism).

Generally speaking, people who were lucky enough to be born later in time have the advantage over people born earlier, since they can learn from those who come before. This isn't something you have to remember when looking at science since science in the news is if anything too focused on speculation or the latest result over what has been well confirmed - but philosophy has the opposite problem. People still talk about philosophers with ancient names, heavy with dignity even though their ideas have been challenged or extended since their time.

Really, nobody talking about truth should be failing to make a distinction between what is true and what is know since Godel did his work, but Descartes had the disadvantage of being born to early to know about that. In particular, his justifications fall afoul of the third horn of the Münchhausen Trilemma, by resorting to assuming some things as axiomatic. In particular, on reflection I'm baffled that Laplace can take "I think" as axiomatic but not "I am". Existence without though isn't hard to imagine (and some Laplacian demon might be imposing its thoughts on us), but thoughts without existence is. Perhaps if Laplace hadn't set out to prove the existence of God he wouldn't have had to make such odd assumptions.

>> A curious thing about the ontological problem is its simplicity. It can be put in three Anglo-Saxon monosyllables: ‘What is there?’ It can be answered, moreover, in a word—‘Everything’—and everyone will accept this answer as true. However, this is merely to say that there is what there is. There remains room for disagreement over cases; and so the issue has stayed alive down the centuries.

[1] Online: http://en.wikisource.org/wiki/On_What_There_Is

[2] Original source: http://www.jstor.org/pss/20123117

Asking what philosophy book to read is sort of like asking which math book to read.

The answer really depends on what you already know. You're probably not going to recommend that someone completely unfamiliar with math read a calculus textbook, much less an advanced math monogram.

Likewise, it's probably not a good idea to recommend that someone unfamiliar with philosophy read Heidegger. You're probably going to get some very basic recommendations.

Even then, you probably won't get much out of reading them without taking a class on the subject in which someone with vastly more experience and understanding than you can guide you and your peers to gain a greater appreciation of what you read, and to stimulate critical thought and discussion about the books you are reading. That's really the ideal setting for getting introduced to philosophy: as part of a class led by a talented teacher, and with some intelligent peers open to talking about the issues.

That said, you should not allow yourself to be misled in to thinking the toe that you dip in to the ocean of philosophy is going to be in any way representative, much less the "best" that philosophy has to offer.

Even were you to read a "great" book when you just start out, you're probably not going to understand much of it or get much out of it on your first go. Even professional philosophers go back again and again to classics, as they get more out of them each time, with the benefit of greater understanding, and being able to apply the insight and methods they've gained in the meantime to the books they've already read.

What I'm trying to say is that reading philosophy in a way that does justice to the topic is a lifetime endeavor. A one-time bite at any philosophy book just isn't going to give you even an inkling of an idea of what it's about.

Still, for an introduction to Western philosophy, you probably won't be able to do better than starting with the Socratic Dialogues. They are the source and the foundation of much of Western philosophy that's come afterwards, and you really can't properly understand most of the rest without reading this source.

I would strongly encourage you to read them as part of an Ancient Philosophy class at a university, for the reasons mentioned a few paragraphs earlier. Unfortunately, the philosophy departments of universities in the English speaking world tend to be dominated by the Analytic school of philosophy. So what you'll get from class will probably be biased in that direction. Just keep in mind that there are other ways of approaching and understanding the issues you read about than the ones you are exposed to in class.

Plato's Dialogues and the Pre-Socratics, written 2500 years ago. By reading the above works you'll see that they contained all the important questions.

Your issue here seems to be "this doesn't answer the question I want therefore this is useless". This is just a lack of imagination on your part. Sure, he doesn't delve into the nature of what it means to exist, but "I think therefore I am" crosses a huge chasm in its own right. It establishes existence. One needs to do this before you can begin to discuss the nature of existence.

The "uselessness" of philosophy for most people, and I think this is where it fails for you, is that it provides far more questions than it provides answers. Philosophy doesn't package the world into a neat little box; it provides you with a framework to develop your own understanding of it. You still have to do much of the mental legwork yourself. Contrast this with science, where it does provide you with neat little bite-sized answers to satisfy ones superficial curiosity (E=mc^2? Cool!)

Vx [x thinks > x exists].

You also seem to think that Descartes needs to provide an accont of what it means to exist. Why think that? You speak English. 'Exists' is a perfectly intelligible English word. And so we can understand the conclusion and the explicit assumption.

Of course, it is an interesting philosophical question as to what existence amounts to. Quite a hard one. But it's a different philosophical question.

You seem to be criticising Descartes for not answering that question, but that's just to conflate distinct issues.

It's also a little incoherent to say that philosophy is useless because it ignores certain questions, which then turn out on inspection to be further philosophical questions.

And philosophers do grapple with what existence amounts to. Go read some Quine if you're actually interested.

In fact, Quine provides an account of existence which vindicates teh implicit premise I've outlined above. But Quine is writing 400 years after Descartes, after the great philosophical revolution brought about by the logical developmenets of the philosopher Frege (which incidentially had an impact on computing and so on). So we might say that Descartes doesn't answer the questions you raise fully. But only someone a little up their own arse would criticise Descartes for failing to deal with questions it took 400 years of philosophical, logical and mathematical development to make substantive progress on.

That's the thing, philosophy doesn't have to be practical, it stands by itself above everything else, with maybe only Maths as a worthy companion. You can either make fun of this, like Aristophanes already did 2,500 years ago in The Clouds, or you can take it as it is.