There are probably a lot more words spilled on this topic in more eloquent and thoughtful ways elsewhere. I don’t know where yet, but I’ll find ‘em, and when I do, I’ll point you there. If you know of some, please fill me in, I’m interested.
I’ll just say now that this is a horribly cited post – I say a lot of things without necessarily backing them up, but where I have easy access to evidence (i.e. on a website not a book) I’ll link to things.
Once upon a time there was a philosopher named Hegel. He’s most commonly known for his philosophy of history, which he described as dialectical, or a dialogue between ideas. You’d have a thesis, an antithesis, and then out of the two would arise a synthesis. Then the synthesis would become a thesis (or an antithesis) and the process would continue. Think of it like a equilateral triangle: thesis is on one bottom point, the antithesis is on the other, and the synthesis is on top. Through this history, philosophy, and humanity were constantly progressing. Lots and lots of triangles.
One of the terms Hegel popularized was zeitgeist. It’s a German word that refers to the spirit of an age, literally time spirit or time ghost. It refers to the collective consciousness of a society, and how that consciousness makes itself known in many areas of life. For example, the advances in science and technology during the Industrial Revolution were accompanied by/enabled by a particular way of thinking about human beings. The human body was considered a machine, the way humans worked was made machine-like (factories) etc.
Bottom line: you do nothing in a vacuum. The way that we exist as human beings, as people in particular country, in a particular time, doing a particular job, are all influenced by and influencing one another.
Agile is a manifestation of a Zeitgeist. It’s founded on a particular answer to the question of what it means to be a human being. It says that humans work well in voluntary communities – self-organizing, organic, cross functional. It says that we need ceremonies and that time is best thought of as cyclical, not linear. It says that we know very few things for certain, so we should only act on the things we know. It says that change is constant and ought to be embraced, not feared. (Agile Manifesto here.)
The Fun Part:
These same answers/principles pop up in completely unrelated areas, but in ways that are bizarrely identical. For example, there’s entire paragraphs that I’ve read from Alistair Cockburn that totally match paragraphs in certain strains of contemporary Protestant theology. Not in a plagarism way, but in a thought-process way. Both have a strong emphasis on community, intentional communication, relational evangelism, evolving knowledge and process, self-aware and reflective. I need to go find the books I read that had these paragraphs in them, and when I do, I’ll post them here.
If you think of waterfall as modern and agile as postmodern, it all makes sense. Anything that is self-aware defines itself both by what it is (positively) and what it isn’t (negatively.) Waterfall is mechanistic: people are silo’d into functional roles and development is heavily process driven. It’s a serial process. Agile is defined positively as organic, communal, and change-oriented, a parallel process, and negatively as not mechanistic (i.e. agile is a perpetual experiment, not a gantt chart.) Fundamentalist Protestant theology in the 19th/20th century was mechanistic, in the sense that truth could be gained in a clean room – all I need is Jesus and my Bible, and I can understand absolute truth, no context required, literal meaning of the text, etc. Particular trains of current Protestant theology* define themselves positively as organic, context driven, experimental, a cyclical view of time, open to change and diversity, and negatively as not fundamentalist. (Example here, and here.)
There are doubtless a lot of other examples out there. This is just one I happen to know well.