An argument against idealism
Premise 1: All that is mental is directed to something. Premise 2: Mental things exists. Premise 3: Mental things can be directed to mental things. Theorem 1: Chains of mental things directed to mental things can exist. (P3, UI, MI) Theorem 2: If all that exists is mental, all that exists is a chain of mental direction. (1, 3, UI, ACP) Premise 4: An endless chain of mental direction (be it endless due to looping in on itself or going on infinitely) is meaningless. Theorem 3: if all that exists is a chain of mental direction, nothing meaningful exists. (P4, UI, ACP) Theorem 4: If all that exists is mental, nothing meaningful exists. (T2, T3, CP) Premise 4: Something meaningful exists. Conclusion: Not everything is mental. (T4, P4, MT) Defense of premises and theorems: Defense of premise 1: To be conscious is always to be conscious 'of' something, so awareness is awareness of something, experience experience of something; thought is always thought about something, conception or...