Abstract
This article discusses three different approaches to human knowledge. The first is that of Peter Simons, a linguistic philosopher, who suggests that language has an underlying algebraic structure. The second approach is that of Ernest Nagel, a philosopher of science, who maintains that the key to knowledge lies in logical analysis. The third approach, due to Michael Polanyi, stresses the idea of tacit integration of parts into composite wholes. All three employ hierarchical schemes, the first two work from the top down, whereas Polanyi works from the bottom up, using the idea of ‘emergence’