Question

I hear this phrase often and do not fully understand it’s meaning. What does it mean? And if possible, is there an example?

thank you!

Answer 1

One use of this expression refers to a style of programming where there is a very deep call stack. You might see a method called Grobble and wonder what it does, so you open up the definition and see this:

class FooHandler
{
    void Grobble(Foo foo)
    {
        foo.Grobble();
    }
}

So then you look at Foo.Grobble:

class Foo
{
    FooImpl _fooImpl;

    void Grobble()
    {
        _fooImpl.Grobble();
    }
}

That takes you too FooImpl which looks like this:

class FooImpl
{
    void Grobble()
    {
        this.Grobble(false);
    }

    // etc...
}

After going deeper and deeper into the code, still unable to see the end, you are allowed to frustratedly exclaim “It’s turtles all the way down!”

The reference is to the metaphor of the Earth being on the back of a turtle. What is the turtle standing on? Another turtle… etc.