Max Tegmark has written a new book entitled Our Mathematical Universe in which he defines the Mathematical Universe Hypothesis (MUH): Our external physical reality is a mathematical structure. Tegmark defines this structure as "abstract entities with relations between them." He then goes on to introduce "baggage." As he points out in the first page of his 2007 manuscript, "...Such a description [MUH] must be expressible in a form that is devoid of human 'baggage'." Is Tegmark referring to what we know as models and the human activity of modeling? Lord Kelvin, a 19th century physicist, is frequently quoted as "I am never content until I have constructed a mechanical model of what I am studying. If I succeed in making one, I understand; otherwise I do not." Would Tegmark classify Kelvin's models, and all others of this ilk, as baggage? Modeling reflects a fundamental human need to create new languages and expressions as ways of coming to know the world. Some of these languages are typographic in form, others visual and tactile. Human psychology would suggest that models play a critical role in how we think. Perhaps I should enlist in baggage services.
The above picture represents a German mechanical model from the 1890's, now located in the Kyoto University Museum in Japan. The 19th century was a golden age of mechanical modeling, an idea and area which is rapidly reemerging with technologies such as virtual reality and 3D printing. Now, fast forward to the current year (2014). I am grateful to Joselle Kehoe, a colleague in the mathematics department here at UTD, for her discussion on Tegmark's new text. I confess to not having read the new book. My observations are a result of reading the earlier paper.