I'm not sure exactly what you are asking. If you are simply asking whether it is possible then the answer is "yes" and also that scilab has a fuzzy logic toolbox to make this easier (sciFLT). If you are asking how to use this toolbox to combine fuzzy set theory with a particular machine learning approach, then some additional info would help.

If we consider brain as a search motor in clinical decision making, we use test's result and palpation as inputs and the brain gives us as an output a list of possible diagnosis.

I would like to make an experience of machine learning with a fuzzy logic approach. I already use sciFLT to model simple decision making. I would like to make a step forward with the machine learning but I wonder if Scilab could be used for this research.