In the philosophy of mind, Leibniz's gap is the problem that thoughts cannot be observed or perceived solely by examining brain properties, events, and processes.
Here the word "gap" is a metaphor of a subquestion regarding the mind–body problem that allegedly must be answered in order to reach a more profound understanding of qualia, consciousness and emergence.
This must be sought, therefore, in the simple substance, and not in the composite or in the machine.The problem is that there is a gap between concepts of modern neuroscience, and those that we use to describe the brain, such as "thought", "feeling", and "perception".
[3] Leibniz himself sought to bridge the gap by introducing monads to explain the existence of immaterial, eternal souls.
Computationalism seeks to answer the problem proposed by Leibniz's gap through functional analysis of the brain and its processes.