(exerpt from my paper) My attempts to weaken Berkeley's argument are as follows:
Berkeley.1) - For matter to be metaphysically possible the following must be disproved somehow. 1) Matter is a mind independent substance. 2) If something is independent of the mind, it cannot be an idea (it can't be sensible by the mind). 3) Therefore you need to be able to concieve what is inconcievable. 4) As soon as you concieve a substance which is inconcievable, it has just been concieved. 5) The existence of matter is impossible
Hobbes.1) - No rebuttal.
Daniel.1) - There is a gap between concievability and possibility and it is flawed. 1) It is concievable but metaphysically and demonstratably impossible for an even integer four or greater to not be the sum of two odd integers. 2) Possibility does not always follow conceivability. 1) We cannot conceive what it is like to experience sonar vision like a bat but it is not impossible to experience sonar vision like a bat. 2) The power of our imagination is limited. 3) Inconcievability can entail possibility. 4) The existence of noumenal matter is possible, we perhaps just lack the sense organ to percieve it.
Berkeley.2) - 1) We percieve ordinary objects. 2) The only aspects of these objects we percieve are their sensible qualities. 3) Sensible qualities cannot exist without the mind. 4) Ordinary objects are ideas. 4) We have no direct contact with "matter".
Hobbes.2) - No rebuttal.
Daniel.2) - Okay? All you accomplished to prove was that the phenomenal world - what we perceive - is dependent on our perception. DUH! Sure, we have no need for matter yet but that time will come.
Berkeley.3.a) - Berkeley's argument for god: Ideas can be caused by one of three things - myself, ideas or god. He goes through a process of elimination to state that it is in fact god that causes ideas.
X - Ideas - 1) Since ideas are mind dependent they cannot have characteristics which are unpercieved. 2) No power or activity is perceived in ideas. 3) Ideas possess no causal power.
Y - Myself - 1) Ideas are mind-dependent, a mind must cause them to exist. 2) There are some ideas which I do not consciously will to exist. 3) I do not cause those ideas.
Z - God - It follows that ideas are caused by another spirit. That spirit is god.
Hobbes.3) - 1) A body/substance is defined as a thing that takes up space. 2) Incorporeal is defined as the quality of not being composed of matter. 3) A spirit is defined as an incorporeal body. 4) A body cannot be incorporeal. 5) The definition of spirit is contradictory
Berkeley.3.b) - 1) Berkeley never gives a definition for body, incorporeal or spirit however I'm sure he would argue that his definition of body is flawed and should instead be defined as an idea that appears to take up space. 2) He would also argue that incorporeal should instead be defined as quality of not being composed of ideas. 3) Lastly he would argue that a spirit should be defined as as an incorporeal perceiver.
Daniel.3) - Berkeley does dodge the threat of contradiction however (in Berkeley.3.A.Y.) his argument that ideas aren't caused by my mind is flawed. a) It is based on the assumption that we can only cause ideas when we are conscious and 2) that we can only cause ideas through our will. 3) I can concieve that there is an unconscious mind which resides within my brain and who has the capacity to manifest phenomena in my environment without my willing it to happen. 4) It is possible that my mind alone causes all idea to manifest and subsist. 5) It is also possible that all of the knowledge in the universe is innate in me and I unconsciously manifest it at random.