這篇 The Unintentional Side Effect of a Bad Concurrency Model 出自 Joe Armstrong 的 blog 。文章裡提到的 Erlang 世界觀，跟 Robert C. Martin 主張的 Clean Architecture 相左。 Robert C. Martin 認為：「 micro-services 只是一種 deploy 的選項 ，並不是 Architecture 。」然而在 Erlang 的世界觀卻不這麼認為，在 Erlang programmer 的世界觀認為：
(1) micro-services 的設計，才應該是 default 的選項。我們應該要透過不停地在系統中加入新的小型獨立的 communicating objects 來讓系統成長 (micro-services)，而不是把「不需要溝通」的程式愈寫愈大 (monolithic)。
(2) 模組與模組之間，應該要透過 communication protocol/message 來溝通，而不是依賴於 API 。
而作者的結論是：『為什麼世界上大部分的程式都不是用 erlang 的世界觀在開發，主要就是因為大部分的其它語言都沒有一個好的 concurrency model ，於是就造成了一種未意料到的副作用。』
Sequential languages are designed to write sequential programs, and the only way for a sequential program to grow in functionality is for it to get larger. It's technically difficult to split it into cooperating processes so this is not usually done. The concurrency in the application cannot be used to structure the application.
We should grow things by adding more small communicating objects, rather than making larger and larger non-communicating objects.
Concentrating on the communication provides a higher level of abstraction than concentrating on the function APIs used within the system. Black-box equivalence says that two systems are equivalent if they cannot be distinguished by observing their communication patterns. Two black-boxes are equivalent if they have identical input/output behavior.
