"This Agrees With My Experience".

For example, without philosophy, how would one have known that proving theorems using logic might be a good way to understand things like circles, lines, and shapes (or even came up with the idea of "logic")?

How people like Euclid came up with the methods they did is, I suppose, lost in the mists of history. Were Euclid and his predecessors doing "philosophy"? That's just a definitional question.

The problem is that there is no such thing as philosophy. You cannot go and "do philosophy", in the way that you can "do mathematics" or "do skiing". There are only people thinking, some well and some badly. The less they get out of their armchairs, the more their activity is likely to be called philosophy, and in general, the less useful their activity is likely to be. Mathematics is the only exception, and only superficially, because mathematical objects are clearly outside your head, just as much as physical ones are. You bang up against them, in a way that never happens in philosophy.

When philosophy works, it isn't philosophy any more, so the study of philosophy is the study of what didn't work. It's a subject defined by negation, like the biology of non-elephants. It's like a small town in which you cannot achieve anything of substance except by leaving it. Philosophers are the ones who stay there all their lives.

I realise that I'm doing whatever the opposite is of cutting them some slack. Maybe trussing them up and dumping them in the trash.

I just think we should cut philosophers some slack for doing things that turn out to be unproductive in retrospect, and appreciate more the genuine progress they have made.

What has philosophy ever done for us? :-) I just googled that exact phrase, and the same without the "ever", but none of the hits gave a satisfactory defence. In fact, I turned up this quote from the philosopher Austin, characterising philosophy much as I did above:

"It's the dumping ground for all the leftovers from other sciences, where everything turns up which we don't know quite how to take. As soon as someone discovers a reputable and reliable method of handling some portion of these residual problems, a new science is set up, which tends to break away from philosophy."

Responding to the sibling comment here as it's one train of thought:

How might one know, a priori, that "What is a circle?" is a valid question to ask, but not "What is a shape?"

By knowing this without knowing why. That's all that a priori knowledge is: stuff you know without knowing why. Or to make the levels of abstraction more explicit, a priori beliefs are beliefs you have without knowing why. Once you start thinking about them, asking why you believe something and finding reasons to accept or reject it, it's no longer a priori. The way to discover whether either of those questons is sensible is to try answering them and see where that leads you.

That activity is called "philosophy", but only until the process gets traction and goes somewhere. Then it's something else.

Yes, but I haven't, because what would I measure? I seem to have "more energy" from doing these exercises, but I expect that rating "energy" on a 5-point scale would be as impossible as rating "happiness". I could instead keep a log of things done (which is, after all, the point of having "energy"). Come to think of it, that might be useful anyway.

I find it difficult to see any trace of the idea in Euclid. Circles and straight lines, yes, but any abstract idea of shape in general, if it can be read into geometry at all, would only be in the modern axiomatisation. And done by mathematicians finding actual theorems, not by philosophers assuming there is an actual thing behind our use of the word, that it is their task to discover.

Well, I did just post my thinking about that, and I feel like I'm the only person pointing out that Putnam and the rest are arguing the acoustics of unheard falling trees. To me, the issue is dissolved so thoroughly that there isn't a question left, other than the real questions of what's going on in our brains when we talk.

It still looks to me like arguing about a wrong question. We use words to communicate with each other, which requires that by and large we learn to use the same words in similar ways. There are interesting questions to ask about how we do this, but questions of a sort that require doing real work to discover answers. To philosophically ask, "Ah, but what what sort of thing is a meaning? What are meanings? What is the process of referring?" is nugatory.

It is as if one were to look at the shapes that crystals grow into and ask not, "What mechanisms produce these shapes?" (a question answered in the laboratory, not the armchair, by discovering that atoms bind to each other in ways that form orderly lattices), but "What is a shape?"

As I see it, the job of philosophy is to clear up our own conceptual confusions; that's not the sort of thing that ever could conflict with science!

It certainly can, if the job is done badly.

Agreed that Grisdale's argument isn't very good, I have a hard time taking Putnam's argument seriously, or even the whole context in which he presented his thought experiment. Like a lot of philosophy, it reminds me of a bunch of maths noobs arguing long and futilely in a not-even-wrong manner over whether 0.999...=1.

We on Earth use "water" to refer to a certain substance; those on Twin Earth use "water" to refer to a different substance with many of the same properties; our scientists and theirs meet with samples of the respective substances, discover their constitutions are actually diffferent, and henceforth change their terminology to make it clear, when it needs to be, which of the two substances is being referred to in any particular case.

There is no problem here to solve.

For qualia, that is precisely the definition of the word, and therefore says nothing to explain their existence. For consciousness, it also comes down to a definition, given a reasonable guess at what is meant by "intelligence" in this context.

What is this "inside"?

None of this rises to the level of Quantified Self Geek, but for the last few years I've been measuring a few things, using an ordinary spreadsheet:

• Weight, every day, same time every day, for about 7 years now. Leaving aside occasional excursions (in either direction) due to ill-health, the long-term trend is flat, but I have noticed a strong relationship between day-to-day weight and how well I feel. Above 125 pounds or below 120 I can tell there's something wrong.

• My daily exercises, "every" day. I actually average about 5 days out of 7 -- which I only know because I have the record. This I've been doing for three years, ever since I started doing a fixed set of exercises every day. I do other exercise, but this is the only part I record, just to keep me honest. Everything else is as and when.

• Time I went to bed, time I got up, and how I woke (e.g. alarm clock).

• Any transient indispositions.

I once tried recording "happiness", but gave up on it, for reasons described in my comments on that thread.

Not quite the same thing, but in another spreadsheet I record every financial transaction on every store of financial value (current account, credit cards, etc.), organised month by month, and project estimates of everything out to at least a year ahead.

I find that just making records of this sort changes what I do, just from paying attention as a side-effect of recording them, and the accessibility of the data. I'm more likely to do my daily exercises if I see that I skipped them the last few days. I will notice if I'm on track to spend £500 on books this month, and ask myself, "Do I really want to direct this much money in that way?" And it's always worth knowing (years of FY money) = (total financial worth)/(total annual expenditure).

If that community couldn't sustain itself, is there reason to think a subreddit here would prosper any better?

The problem with discussion of AGI, nanotechnology, and all the other "Shock Level N" memes for N ≥ 2 is that there is no real subject matter. For the most part it's just verbal geekery about cool ideas that no-one is actually doing anything about, because they're too far beyond current capabilities. Fine to engage in for a while at an SF con or in a pub with other geeks, but there's only so long you can be at a party before realising you're just seeing the same ideas over and over and it's time to leave.

I never read SL4 -- is that an accurate description of why it died?