@jpcastlin
Ex-lawyer strategy advisor + author. Discoverer of dynamic uncertainty, inventor of the 4E model of market dynamics, creator of frameworks, and PA of (a.k.a. father to) Idun and Edda. As seen on stage, on TV, in books, in newspapers, in columns, etc.
Does size matter? The answer is yes, but not always in the ways that you would have thought.
In this week’s newsletter, we dig into data collection. I hope that you will enjoy it and have a great weekend.
strategyinpraxis.substack.com/p/the-one-on...
As always, I hope that you will like it and have a great weekend.
strategyinpraxis.substack.com/p/the-one-on...
The practical move is to interrogate the fine print: what must stay true for a framework to work, what variables are being held constant, what disturbances will break it, and whether you will update the model when they show up.
In complex systems, clean causality is rare, so analysts import ceteris paribus assumptions; over time these often drift from convenience into “reality”.
People largely resist nuance because it increases uncertainty, and uncertainty feels existentially unsafe.
The instinct to reduce uncertainty drives retrospective coherence: converting ambiguity into neat causal narratives so that actions and outcomes feel controllable.
Is it a bird? Is it a plane? Oh, it’s all the same.
In today’s free-for-all newsletter, we discuss the analytical assumption that all things can be equal.
The TL;DR:
Frameworks, models, and tools are conditional: useful in some contexts, misleading in others.
Holy hell. That big air final.
Well, here we go. Last week’s newsletter on Agile proved controversial; it will be very interesting to see the response to this one. Is diagnosis overrated?
The answer may surprise you.
strategyinpraxis.substack.com/p/the-really...
As always, I hope that you will like it and have a great weekend.
strategyinpraxis.substack.com/p/the-one-on...
Agile comes with a scaling trap that often leads to clashes with governance, funding, and legacy structures. “Agile-at-scale” typically mutates into something else entirely.
The grown-up conversation is not whether one is pro- or anti-Agile, but one of context appropriateness.
The Manifesto’s values are also so abstract that although they provide a strong sales mechanism, they also create a misinterpretation magnet that incentivizes “everyone is Agile now” theater.
Having said that, the Snowbird-era Manifesto language can read like a zero-sum provocation, which helps explain why it gets weaponized.
Agile is often considered to be the antonym of strategy, yet this view reveals more about the commentator’s level of understanding than it does about the approach.
Is that a bird? Is it a plane? It is a bird. No, wait, a plane. I keep changing my mind.
Oh, it’s a newsletter on Agile.
TL;DR:
We all float down here.
As always, I hope that you will like it and have a great weekend!
strategyinpraxis.substack.com/p/the-one-on...
- The same event can be ergodic for the observer and non-ergodic for the participant; there is a material difference between being a gambler and being a gamble.
- Long-term strategy should optimize for staying in the proverbial game over winning it; one cannot thrive if one does not survive.
- In the short-term, performance dominates. Over time, it does not.
- Industry benchmarks and market averages can mislead when there are points of no return, compounding effects, or irreversible downside.
Is it a flock, or a single bird repeating its average behavior at the moment? Why, no - it is a newsletter on ergodicity!
The TL;DR
- Ergodicity ends when yesterday’s outcome changes tomorrow’s odds, which quietly breaks many assumptions in strategy.
Decisions have latency. When the firm’s tempo lags the world’s tempo, feedback delays become exposure.
As always, I hope that you will like it and have a great weekend.
strategyinpraxis.substack.com/p/the-one-on...
Even known probabilities are not stable: repeated action can alter the underlying system, turning that which is believed to be predictable into something that is not.
Assumptions have a half-life. Strategy becomes fragile when firms treat different assumptions as having identical durability.
Strategy, at its core, is about managing uncertainty over time to move in a wanted direction, but time also changes the uncertainty firms must face in scope, scale, and nature.
Is it a bird? Is it a plane? No, it is a newsletter on strategy, uncertainty, and time.
The TL;DR:
The obvious answers to one of strategy’s most important questions do not survive scrutiny; they are either too universal to be useful in practice or confuse outcomes with strategy itself.
As always, I hope that you will like it and have a great weekend.
strategyinpraxis.substack.com/p/the-one-on...
5. A different approach is to utilize adaptive ethics almost as system design: ensure decision ownership and transparency, enable bottom-up feedback, and keep principles stable while updating application through iteration.
3. Morality evolves. Many conventional corporate ethics frameworks assume a stable landscape, but values shift across time, cultures, and through our own actions.
4. When norms shift, decision-makers tend to fail in two ways: by rigidly clinging on to outdated rules or by improvising incoherently.
2. The desire to reduce uncertainty obviously exists in organizations too. Shared values and codes can coordinate action, lower stress, and accelerate decisions under ambiguity.
TL;DR:
1. Ethics and moral norms are tools for reducing perceived uncertainty, helping us predict acceptable behavior (both our own and others’) in an otherwise opaque future.
Is it a shooting star? Is it fireworks? No, it is the first newsletter of the year!
Today, we discuss morality and ethics as tools with which to reduce perceived uncertainty, how organizations go wrong when they try to navigate the moral landscape, and what they ought to do instead.
Is it a bunch of fireflies? Are those fireworks? No, it is the final free-for-all newsletter of 2025.
Today, we round off the year by looking back at the past twelve months and ahead to those that will come.
From the bottom of my heart, thank you for subscribing. 2026 will be better than ever.