In a recent issue of Food Technology, the magazine for IFT members, Hervé This responds to the suggestion that molecular gastronomy is part culinary art and part science. He gives a very good summary of the differences between cookery/culinary, food science and food technology:
“Cooking is a technique (sometimes an art) and the objective is to make food.”
“On the other hand, molecular gastronomy is a science. It is performed in a laboratory.”
“Furthermore, science is not technology. Thus, applied science cannot exist. Application involves technology (from techne, doing, and logos, study). When examining mechanisms of phenomena, the goal is not to apply knowledge (application), but rather to produce it.”
He admits that he himself had problems during his thesis of separating out science from technology but he states very strongly that molecular gastronomy is science and molecular cooking is using the results from molecular gastronomy to create new food items or improve old ones. This’ Ph.D. thesis, on Physical Chemistry of Materials, was entitled Molecular and Physical Gastronomy or the equivalent in French.
The confusion between the science, art and technology of food is present in food science. That there does not appear to be a final definition of molecular gastronomy adds to this confusion, especially as chefs have taken over this term, rather than using This’ preferred Molecular Cooking. Khymos gives a good summary of the different definitions.
I do have problems with the fact that Molecular Gastronomy is so trendy and considered to be the saving of the world’s food supply. [So I exaggerate? What’s the problem?] Many articles about Molecular Gastronomy and the restaurants that practice molecular cookery appear to have never heard of food science. So I appreciated the fact that This states that molecular gastronomy is part of food science but I struggle to place it within the traditional subject areas of food science. It overlaps mostly with food chemistry. At least This’ part of Molecular Gastronomy is heavily physical chemistry based. The research undertaken is more directly relevant to cooking and culinary arts than much of food chemistry. For example, my research on the Maillard reaction has few direct practical applications, unless you are willing to mix amino acids and sugars together in your kitchen. I still would not recommend eating the results of my research.
Within the article he gives an excellent summary of what science is – the idea of testing a hypothesis to give new information which increases our knowledge of a system. I might even use some of these ideas for teaching.
References
Hervé This Molecular Gastronomy vs. Molecular Cooking Food Technology December 2008 (PDF)
Lab Cat 
I am not a scientist. Nor am I a foodie. I am just your average Jill who enjoys nonfiction. I have read Herve This’ book on Molecular Gastronomy and the Science of Flavour. I found it to be fascinating. I thought of it as a science book and not particularly relevant to cultural/social aspects of food — growing, harvesting/processing/distributing, consuming. I am also interested in these fields.