Alas, by themselves7, the apparatus of operations over variables tells nothing about 
learning.  

It is from there that the basic need for hybrid architectures that combine symbol-
manipulation with other techniques such as deep learning most fundamentally 
emerges. Deep learning has raised the bar for learning, particularly from large data sets, 
symbol manipulation has set the standard for representing and manipulating 
abstractions. It is clear that we need to bring the two (or something like them8) together.  

2.1.2 Hybrids are often effective
The Next Decade in AI-