This observation comes from Tony Hoare’s essay “Programming is an Engineering Profession”. He notes that established branches of engineering test their advances first on small-scale models, using devices such as wave tanks and wind tunnels before committing to full-size construction.

The practical reasoning is about cost and speed. Building and testing a small model is far cheaper than experimenting on the finished article, so models allow more ideas to be tried and refined. Without them, Hoare suggests, research would be prohibitively expensive and progress would slow accordingly.

In the wider essay, the point supports his argument that programming should mature into an engineering discipline. Just as other engineers rely on models to test designs safely and economically, he implies that software development benefits from comparable ways of trying out ideas at reduced scale before full commitment.