1. Berkeley on Substance Ideas in Mind of God Ideas in Mind1
Ideas are simply what they are they do not inhere in anything else—that is there is
No material substrate
To be is to be perceived=esse es percipi

2. Locke on knowing the world
SELF
WORLD
Substance=“A something
I know not what.’
Act of Reflection
Primary Qualities
In Mind
Primary Qualities in Things
Secondary Qualities
Substance is in principle unknowable

3. Aristotle on Knowing the World
Matter=substrate/potential
Form=matter in act
Potential=matter/substrate
Potential=Mental Substrate
Abstracted Forms being
Thought in Mind
SUBJECT=SOUL/MIND
OBJECT
Actual Field of Perceptual Interaction
Material substrate=upokeimenon
The Mind is in a Sense All Things
The Mind(Soul) will, through time, exhaust all potential forms and powers of an object—it will fully know it. There is nothing that is, in principle, unknowable

4. Descartes on Knowing the World
Mental Substance
Thinking Thing
Non-spatial
Material Substances
Extended things
Pineal Gland
What are we thinking about an object may in no way correspond to any actual Characteristic in
the thing it-self (cf. evil genius). There is no direct connection between mind and world.