If you blog it they will come?

Monday, March 26, 2012

"We have a false model of what thinking is"

This is a tasty excerpt from a great interview with David Graeber:

We have a false model of what thinking is. Because you can't really think by yourself, can you? You have to create someone else in your mind to explain things to, and to have an imaginary conversation with. This idea was inspired in part by the philosopher of cybernetics, Andy Clark, who proposed something he calls the extended mind hypothesis. Basically, the argument goes like this: Say you're doing long division on a piece of paper instead of doing it in your head. Clark asks why the piece of paper is not just as much a part of your mind while you're doing that calculation as the part of your brain that's doing the math. He says there's no reason at all.There are a million similar examples that philosophers like to trundle out—you have a bad memory so you write everything down. Is that piece of paper then part of your mind?

"Mind" isn't "brain"— the brain is just an organ; your mind is the dynamic interaction of various moving elements that culminates in thought. Philosophers like Clark are willing to take that argument this far, but the question that never seems to occur to them is this: when you're having a conversation with someone else, is their mind part of your mind? Nowadays, many philosophers of consciousness like to note just how razor-thin this thing we call "consciousness", that self-aware part of our mental operations, really is. The average person can rarely hold a thought for more than three or four seconds, eight at the most, before the mind wanders. It's very unusual to be fully conscious for more than a tiny window of time. That is, unless you're having a conversation with someone else, in which case you can often do it for long periods of time, especially if the conversation is with someone you find particularly interesting. In other words, most of the time we're conscious is when we're talking to someone else, or otherwise interacting intensely; during moments in which when we're not clear whose mind is whose. So consciousness is interactive, it's dyadic or triadic. It's a fallacy to imagine that thinking is something you largely do alone. On some level, of course, we already know that. But I don't think we've even begun to explore the full implications.

Monday, March 12, 2012

error: unknown warning group

I try and write about really frustrating issues that I manage to figure out or interesting problems that I solve in hopes that it will help other poor developer souls who would otherwise be without a guiding light. Here's an Xcode-inspired episode of the former.

I decided to see what would happen if we moved our iOS project to Xcode 4.3 and it nearly went without a hitch except that I spent several hours trying to figure out why our rake scripts weren't working.

...actually let me back up a step and describe a couple of tools we use.

We use Cedar to run automated tests ("Specs" to follow the parlance of rspec), and one Cool Thing is that they can be run in Xcode or from the command line using rake.

Another Cool Thing, or at least a Thing That Used To Be Cool Before Upgrading Xcode, was our use of PivotalCoreKit to make spec writing more convenient.

PivotalCoreKit uses (abuses?) the dynamic-ness of Objective-C categories to override existing class behavior and suppress NSUrl from making an actual network connection, for example. The advent of 4.3 discourages this sort of flippancy and will issue a warning/error by default, which the newest commit of PivotalCoreKit suppresses with pragma preprocessor macros.

Now is where the wonkiness really starts. Running our specs from Xcode went swimmingly after updating PivotalCoreKit, but building the same spec target from the command line would fail with errors such as:

Externals/PivotalCoreKit/SpecHelperLib/Extensions/UIWebView+Spec.m:4:34: error: unknown warning group '-Wobjc-protocol-method-implementation', ignored [-Werror,-Wunknown-pragmas,2]
#pragma clang diagnostic ignored "-Wobjc-protocol-method-implementation"

What the heck??? They are the same target!

But after comparing the build outputs of Xcode 4.3 and the command line spec script, they were drastically different. For one, I could not get the command line to compile with SDK 5.1. Despite my various environment variable tweaks, the -isysroot parameter pointed firmly at yesterday's SDK.

Here's how I (eventually) fixed it:

  • I ran
    xcodebuild -version
    and found out I was *still* on Xcode 4.2 (I had decided not to delete it yet)!

  • I warily installed the latest command line tools (Apple: "The command-line tools are not bundled with Xcode 4.3 by default. Instead, they can be installed optionally using the Components tab of the Downloads preferences panel")

  • After installing the latest command line tools I was still on 4.2. After digging in /usr/bin/ to ensure that xcodebuild had in fact been updated, I serendipitously discovered

  • sudo xcode-select -switch /Applications/Xcode.app/

  • xcodebuild -version
    is now 4.3!!

  • All is well is command line specs land

So here I am 4 hours later to administer the following advice:
--Delete old versions of Xcode when installing the latest if possible
--Otherwise, remember always: xcode-select -version