Dear Sir/Madam,

Maybe it is of interest to you that I have written a little computer
program that models the basic principles of Thomistic metaphysics. I wrote this simulation program to better digest the underlying concepts and to be better equipped to form my own opinion
of the validity of Mr. Hans-Eduard Hengstenberg's critique of the Thomistic constitutive principles of a being
as being. Mr. Hengstenberg cannot see that "wholeness" of a being can be explained by the Thomistic approach. I have the feeling that my little program just shows the opposite.

I am enclosing a very brief description of "ontosimula" as I have called the program. If you would like to see it in action, please go to: http://www.lambda-bound.de
Sincerely, George P. Loczewski, gpl@lambda-bound.de

                                  Ontosimula

A simplified executable model of the principles of "metaphysics"
by George P. Loczewski

Introduction:
"ontosimula" models the principles of thomistic metaphisics in the form of a computer simulation program. The model illustrates the following metaphysical concepts:
"act-of-to-be", "essence in the wide sense",
"essence in the strict sense (fully individuated essence)",
"correlationship between 'act-of-to-be' and 'essence' "
"first principle of identity" ('unum sequitur esse')
"first principle of intelligibility" ('verum sequitur esse')
"first principle of causality" (participated beings must be caused)
"first principle of finality" ('omne agens agit propter finem' and
             'bonum sequitur esse')
"participated being"
"change of essence" (by growing older for example),
"freedom of person to make decisions" (the program is not
          deterministic).
"analogy of being"

The program is written in "Scheme", a programming language that
combines utmost simplicity with extreme expressiveness due to its root in and its loyalty to the "Lambda Calculus". The program as such could be run in any full Scheme environment following the R4RS standard, but due to the graphical animation in the simulation the "DrScheme" implementation of Scheme is required. "DrScheme" has been developed by the "Programming Languages Theory" group at Rice University at Houston Texas and can be obtained from theํr Web site at: http://www.cs.rice.edu/CS/PLT/

Resources used in building the implementation:

The implementation was strongly influenced by the following books:
"Programmer avec Scheme" by Jacques Chazarain (meta-object protocol),
"The Programming Language Scheme" by R.Kent Dybvig (multitasking)
"Scheme and the Art of Programming" by George Springer and
      Daniel P. Friedman (algorithm for pseudo-random numbers)
"A Little Smalltalk" by Timothy Budd ("Dining Philosophers Problem", originally introduced by Edsgar W. Dijkstra)

From the philosophical side the following books were referenced:
"An Introduction to Philosophy" by Jacques Maritain and
"Thomistic Metaphisics: An Enquiry into the Act of Existing" by
          Charles A. Hart.