## Geometrical Knowledge

Geometrical Knowledge How do we come to have geometrical knowledge? How do we acquire geometrical concepts? The question has been around since Plato and his theory is still probably the best—we have such knowledge innately. But this doesn’t answer the question of what triggers the innate knowledge (it isn’t there fully formed from the start): […]

## Quantifier Logics

Quantified Logics Standard propositional logic contains no quantifiers. It simply replaces sentences with propositional variables (“schematic letters”) that remain unbound. But there is nothing to prevent us from introducing quantifiers that bind these variables, ranging over propositions. These can be objectual or substitutional, according to taste. They will be read “for all p” and “for […]

## Other Bodies

Other Bodies The orthodox view of our knowledge of minds is that while other people’s minds are doubtful my own mind is not: I can be certain of my mind but not of other minds. Hence there is a skeptical problem of other minds but not of my own mind. There is a deep epistemological […]

Academic Blacklisting A few weeks ago, a fellow philosopher suggested to me that it would be a good idea to produce a book of essays discussing my work, which he would edit. I agreed. He contacted Wiley publishers and received a highly enthusiastic response from their commissioning editor Will Croft. It only remained to sign […]

## Cogito for the External World

Cogito for the External World The traditional Cogito “I think, therefore I am” yields a moderate harvest of existential conclusions: the existence of a subject of thoughts (albeit momentary and etiolated) and the existence of propositions as the content of thoughts. We might compare this to a plant that is rooted in the earth and […]

## Formulating the Cogito

Formulating the Cogito The Cogito is usually expressed in the words “I think, therefore I am”. The first clause is misleading: it suggests the proposition that I am a thinker, i.e., that I think things at different times. I might assert this because I remember thinking something yesterday and expect to think something five minutes […]

## Do I Know That I Exist?

Do I Know That I Exist? I am going to argue (a) that the Cogito cannot prove that I exist but (b) that it can prove that various other things exist. This is ironic given that it is commonly supposed that the Cogito can establish the existence of the self (person, subject) but that only […]

## Wittgenstein’s Ontology

Wittgenstein’s Ontology The Tractatus begins with Wittgenstein’s ontology: facts, totalities of facts, states of affairs, objects, combinations of objects, etc. By contrast, the Investigations does not begin in that way: it begins with language—and it goes on in the same way. No reader could hazard a guess as to Wittgenstein’s ontology in the Investigations. Certainly, […]