Alan Kay models these different ways of knowing and interacting with the world by reorganizing the traditional “STEM” acronym into TEMS, representing the historical progression of Tinkering, Engineering, Mathematics, and Science. He views these four domains as an overlapping Venn diagram, where each area has its own distinct properties, goals, and appeal to different personality types.
Tinkering Tinkering (or hacking) is the earliest and most ad hoc approach to creating things. While Kay acknowledges that tinkering is highly useful and serves as the historical root of engineering, he warns that a major problem arises when people confuse mere tinkering with actual, principled engineering.
Engineering Engineering predates science by thousands of years because humans discovered how to build and repair things in “principled ways” without necessarily understanding the deep, underlying “why” of how they worked. Engineering is driven by a moral mandate for safety and integrity. Kay likens this to an engineer’s Hippocratic Oath: “the building must not topple, the bridge must not fall, the plane must not crash”. Good engineers design systems to handle complexity and test them under controlled conditions to ensure they will not fail when deployed to the public.
Mathematics Math began with a “cookbooky” approach but was eventually revolutionized by the introduction of connected reasoning and proofs. It acts as a powerful representational system to model relationships and allow for deep reasoning. Kay points out that mathematics allows us to create absolute “truths” because it is a language that refers only to itself, though these mathematical truths must be carefully distinguished from the approximate reality of the physical world.
Science Modern science is a relatively recent invention, originating about 400 years ago as a “new instrumentality” to get around the natural cognitive biases, flaws, and “stories” generated by our “bad brains”. Science is defined by the principled attempt to gather phenomena and create models, with the actual “knowledge” existing in the continuous negotiation between the model and the real-world phenomena. Unlike engineers, who must avoid failure at all costs to ensure safety, scientists actively try to break their creations and theories, knowing that failure is how they learn and that they will never have the final word.
The TEMS Intersection Kay argues that the most powerful advancements happen in the overlapping “sweet spot” of this TEMS Venn diagram. He notes that the invention of modern science, particularly the rigorous theories of Newton’s Principia, exerted a massive “magnetic field” that pulled tinkering, engineering, and math much closer together.
When evaluating the software industry, Kay frequently critiques it for remaining largely stuck in the “tinkering” phase—making things without real understanding—rather than operating as a true science or engineering discipline. He advocates that computer science should be the “science of processes” that scientifically studies the phenomena of software, while software engineering must adopt the rigorous design, simulation, and fabrication (CAD-SIM-FAB) methods found in mature physical engineering fields.