From a purely physicalist perspective, not only labour, capital and land would have to be included into the set of factors of production, but a potentially unlimited number of elements: fresh air, wind, insects (for pollination), the sun, gravity, etc.. Of course, including all of these things into an economic theory of production would be silly. However, as you will undoubtedly admit, the two most fundamental economic phenomena are production and exchange. Claiming that we need no economic theory of production leaves us with the serious question what economic theory should be all about. Should economics just be a special branch of mathematics or physics? This would undoubtedly contradict your answer to the first question that economics is a science in its own right. And without a theoretical understanding of the production of goods and services, how can there be exchange of those very goods and services? Therefore, your answer cannot be accepted.