Idealism Idealism: nothing exists that exists independently of minds. –Berkeley: To be is to be perceived (or to perceive): esse est percipi (aut percipere) What is a material object, exactly? We think it is mind-independent, but does this make sense?
Why idealism? Objection to naïve realism: secondary qualities are subjective, so we dont perceive objects just as they are. Objection to representative realism: primary qualities do not resemble objects any more than secondary qualities do. So no qualities of material objects are mind- independent; we perceive only ideas. Material objects are just bundles of ideas. If we are not idealists, we will fall into confusion or scepticism.
What causes perceptions? Options: ideas, my mind, another mind –Not ideas: they are passive –Not my mind: perception is very different from imagining –So another mind - given the systematicity and complexity of what we perceive, that mind must be God Is appealing to God any worse than appealing to material objects? They dont explain perception either, e.g. how do they cause ideas?
Illusion and reality How do I distinguish my ideas from reality (ideas outside my mind)? –A perception is not voluntary –The idea perceived is part of the order of nature (coherent reality) –The idea is caused by the mind of God What of illusions? –We arent wrong - it is bent. But we make a mistake if we think it would still be bent out of water. To mark this, we rightly say, The pencil looks bent.
In, out, in, out When objects are not being perceived, then they dont exist! There was a young man who said, God must find it exceedingly odd when He finds that the tree continues to be when no ones about in the Quad. Courtesy of UCL
Reply 1 To say an object of perception exists is to say that it is or can be perceived. But this conflicts with esse est percipi - to be is to be perceived. But should we worry if objects pop in and out of existence if they do so with complete regularity?
Reply 2: Gods response Dear Sir, your astonishments odd, Im always about in the Quad. And thats why the tree continues to be since observed by, yours faithfully, God Ideas we perceive are not just caused by Gods mind, but exist in Gods mind
A final objection Gods mind cant contain the kind of perceptions (partial, visual, etc.) that we have. God is said to be unchanging, but reality changes all the time. Response: the ideas dont exist in Gods mind in this way (as thoughts). What we see is what God wills us to perceive (so they exist as intentions).