Can't someone be unshakable in their conviction merely because they are stubborn? Matters are different for the errors of sensory representation.
Cartesian matter does not fill a distinct spatial container; rather, spatial extension is constituted by extended matter there is no void, or unfilled space.
From this I knew I was a substance whose whole essence or nature is simply to think, and which does not require any place, or depend on any material thing, in order to exist. Non-human analysis such as this, in combination with imaging of the human brain, have contributed to a robust and increasingly predictive theoretical framework.
He considers existence of the external world and whether its perception holds any knowledge of this world Zinn argued that the brain is fully divisible after split brain experiments on dogs.
In these works, which Descartes decided to suppress upon learning of the condemnation of Galileo, he offered a comprehensive vision of the universe as constituted from a bare form of matter having only length, breadth, and depth three-dimensional volume and carved up into particles with size and shape, which may be in motion or at rest, and which interact through laws of motion enforced by God —4.
The justification of the sceptical method of doubting is too shaky to accept. His family wanted Descartes to be a lawyer, like his father and many other relatives.
In the Treatise on Man and Passions, Descartes described purely mechanical processes in the sense organs, brain, and muscles, that were to account for the functions of the sensitive soul.