George Berkeley

1685-1753 · Anglo-Irish · Metaphysics, Epistemology, Philosophy of Perception, Philosophy of Mathematics, Philosophy of Religion

We have first raised a dust and then complain we cannot see.

A brilliant young fellow at Trinity College Dublin announced, before he was twenty-five, that matter does not exist. George Berkeley meant it literally — and spent his life arguing that this was not madness but common sense rescued from the philosophers. Born to an Anglo-Irish family in Kilkenny, he wrote his three great works in a burst of youthful confidence, then chased a doomed dream: a college in Bermuda to educate the New World, for which he sailed to Rhode Island in 1728 and waited three years for funds that never arrived. He returned to become Bishop of Cloyne, and grew old extolling…

Topics George Berkeley addresses

• immaterialism
• esse est percipi
• ideas as the immediate objects of perception
• sensible things as collections of ideas
• spirit as active substance
• the likeness principle
• the rejection of abstract ideas
• the Master Argument
• the collapse of primary and secondary qualities
• God as the cause of ideas
• divine continuous perception
• mind known by notion not by idea
• the ontological dualism of spirit and idea
• esse est percipere
• the language of nature
• the heterogeneity of sight and touch
• the Molyneux problem
• the unperceived perceivable subsisting in the mind of God
• the alleged Berkeleian circle
• the ghosts of departed quantities
• the critique of fluxions and the calculus
• instrumentalist philosophy of physics
• the late Platonic synthesis
• tar-water and the chain of being

Questions to put to George Berkeley

Immaterialism and the New Principle

• What do you mean when you say 'to be is to be perceived'?
• If sensible things are just collections of ideas, what happens to the table when I leave the room?
• How can you say there's no matter when I can clearly touch this desk in front of me?
• What's the difference between an idea and a spirit in your system?
• How do we know spirits exist if we can only perceive ideas?
• Why did you think the hypothesis of material substance was causing so much trouble in philosophy?

The Collapse of Primary and Secondary Qualities

• What's wrong with Locke's distinction between primary and secondary qualities?
• How does the likeness principle work in your argument against matter?
• Can extension or shape exist in matter the way color cannot?
• Why can't we abstract primary qualities from secondary qualities in any real case?
• What do you say to someone who insists that shape is really out there in a way color is not?

The Master Argument and Abstract Ideas

• Can you walk me through the Master Argument about conceiving unperceived objects?
• When I imagine a tree in a forest with no one around, haven't I conceived something existing unperceived?
• What's your objection to Locke's abstract ideas?
• How can there be a general idea of triangle if every triangle I picture has a specific shape?
• Why does rejecting abstract ideas matter so much for your attack on material substance?

God and the Divine Visual Language

• How does God fit into your account of what keeps the world existing?
• What do you mean by calling the visible world a divine language?
• How do you answer the charge that appealing to God is just philosophical sleight of hand?
• What's the difference between your view and Malebranche's vision in God?
• If God causes all our ideas of sense, how do we have any freedom at all?
• How does the regularity of nature show us anything about God's consistency?

Vision, Touch, and the Molyneux Problem

• What's your answer to the Molyneux problem about the man born blind?
• Why do you insist that sight and touch are completely heterogeneous?
• How do we learn to connect what we see with what we touch?
• What did the New Theory of Vision contribute to your larger philosophical project?
• If visible extension and tangible extension are different, which one is the real extension?

The Analyst and the Ghosts of Departed Quantities

• What's your objection to the foundations of the calculus?
• What do you mean by calling differentials 'the ghosts of departed quantities'?
• How can the calculus work in practice if its foundations are unclear?
• Why do you think mathematicians who mock religious mysteries are being hypocritical?
• What would a rigorous account of fluxions and infinitesimals need to show?

Converse with George Berkeley on Simposeum. Replies are grounded in George Berkeley's own writing, cited to the page.