Ground, Groundwork, Foundation

The foundation of a building is its bottommost stratum, while the groundwork of a building is the preparation of the relation between its foundation and the ground that it rests upon.  Thus, 'Groundwork of the Metaphysics of Morals' and 'Foundation of the Metaphysics of Morals' are not equivalent titles of Kant's work.   Now, the classification of Descartes as a 'Foundationalist' is based on that of I Exist as the Foundation of his system, just Spinoza, on the basis of his God/Nature, and Locke, on the basis of Sensations, are similarly classified.  But, often overlooked in such classifications is the preparatory groundwork that precedes them, which, in the case of Descartes, involves the development and implementation of a tool--his Method of Doubt.  But even in that phase of theory-building, overlooked is the nature of the ground itself that requires preparation in order to guarantee the stability of the structure.  Now, that nature cannot be found in the pages of the book itself, so can only, at best, be inferred from what is there.  Now, easily inferred is the fact that Descartes has been at a desk, writing, while affirming his incorporeality.  From there, almost as easily inferred are the circumstances of his act of writing--his Mathematical, Scientific, and Theological interests that have been previously.  So, from that perspective, the structure of which his incorporeal I Exist is the foundation is revealed as a castle in the air, one that has Theological value.