 
Summary: Reality and Probability: Introducing a New Type
of Probability Calculus
Diederik Aerts
Center Leo Apostel (CLEA) and
Foundations of the Exact Sciences (FUND),
Brussels Free University, Krijgskundestraat 33,
1160 Brussels, Belgium.
diraerts@vub.ac.be
Abstract
We consider a conception of reality that is the following: An object
is `real' if we know that if we would try to test whether this object is
present, this test would give us the answer `yes' with certainty. The
knowledge about this certainty we gather from our overall experience
with the world. If we consider a conception of reality where probability
plays a fundamental role, which we should do if we want to incorporate
the microworld into our reality, it can be shown that standard prob
ability theory is not well suited to substitute `certainty' by means of
`probability equal to 1'. We analyze the different problems that arise
when one tries to push standard probability to deliver a conception of
reality as the one we advocate. The analysis of these problems lead us
