James asked:

In an attempt to filter text to ensure that any text my children study has the highest probability of
excellence, I have suggested to them that any modern philosophical text they read should be written
by a philosopher who has demonstrated ability in pure mathematics to the level of at least a first in
Part 1 of the University of Cambridge Tripos in Pure Math, or to any similar standard. Philosophers
who do not meet that standard are not necessarily poor philosophers; however I consider that they
have a significantly lower probability of being good ones, and are arguably not worth the investment
of one's time to interact with them. I am introducing my two children (12 and 13) to philosophy, initially
ethical, while developing their skills in math, logic and probability. I am interested in the possibility of
their taking a Pathways or Diploma program. However in view of my filter, I would want them to be
tutored only by a philosopher with the appropriate level of math I suggest above. I'd be very grateful
were you to advise if it would be worth their while to apply for admission to the Pathways program.

============

The obvious question is, why? Why do you want to impose this mathematics requirement? I suppose
that the answer might be either (or both): because you think that only those who have that kind of
requirement are intelligent enough to teach philosophy (to your children?); or, that somehow,
mathematical abilities are transferable to philosophy, so that those proficient in math, are likely also to
be proficient in philosophy. So that although, as you allow, mathematical ability (and knowledge) are
not a necessary a necessary condition of philosophical ability, and surely not a sufficient condition,
nevertheless, such ability makes it more likely.

Now, I admit, that a high standard of achievement in any kind of subject that rewards sequential
thinking argues that a person is more likely to be good at the kind of sequential thinking that is
necessary for doing intelligent philosophizing; for instance the ability to follow and assess an
argument, that intuition of mine is just that-an intuition. I don't know what the evidence for it is, and I
don't know whether there is any evidence for it. To give an analogy, chess playing ability has been
studied, and, although you might intuit that mathematical ability might have a high correlation with
chess ability, it turns out that although there is some correlation, it is not nearly as great as the
correlation between the ability to see patterns and chess playing ability. So, our intuitions about such
matters might be way off. Intuitions may suggest connections, but we need evidence to test and
confirm intuitions once we have them.

In fact we don't have a lot of information about what makes a good philosopher: especially since there
is, as you might imagine, not a little disagreement about what a good philosopher is. But, isn't what
you are looking for not so much a good philosopher, for which mathematical ability may be helpful if
not necessary, but a good teacher for your children? For all you know, as we philosophers say, a
priori, mathematical ability may be inimical to the ability to teach well, or teach philosophy well.

But I hope you find what you want: more importantly, what your children need.

Kenneth Stern

Your filtering system seems a bit risky to me. Why not get in touch with Michael Dummett at Oxford
University and ask him to be personal tutor to your children?

Rachel Browne

[Answers to James Howe's question from the PHILOS-L and PHILOSOP professional philosophy
e-mail lists have been collected in my Glass House Philosopher notebook for Tuesday, 1st May. See
Page 101.]

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Glouisel asked:

I wondered if you could help me with the good Bishop of Cloyne.

(1) How does Berkeley explain illusion e.g. a pole that seems to bend in the water (involuntary, vivid)
as opposed to imagination?

(2) Why can only spirits and not ideas cause and does this mean that God is constantly intervening
rather than writing laws and then sitting back?

(3) Isn't our way of perceiving and God's different? Isn't this a problem for Berkeley?

(4) Is the doctrine of abstract ideas supposed to underpin all of Berkeley's arguments against matter
or just the one against substance?

============

(1) Illusion occurs at the phenomenological level of appearance. The illusion is a given and Berkeley
does say that ideas imprinted on the senses, as opposed to imagined ideas, are "real things" but in
the case of an illusion we apply knowledge of things, circumstances and standard conditions. A
perception is more than appearance as it entails a judgement. For Berkeley, ideas are sensations or
experience and a thing is a cluster of ideas. You cannot get the idea of a stick from a visual
experience alone, you need tactile experience to form the concept of a stick because you need to
experience it as firm and unbending. We know the pole in the water is an illusion because we know
the stick is not bent yet will appear to be so in water from experience of other appearances of sticks in
water. Imagination presupposes ideas, so you can imagine that a pole seems to bend in the water,
which is an activity of will.

(2) Ideas are inert, so cannot be causal. Causes are what we talk about, but at the level of
metaphysical explanation, there is only spirit. God is constantly acting rather than intervening and so
he could not rest. His will is the cause of all changes including perceptual changes, so he would have
to constantly cause perception of movement, for instance as well as "the succession of ideas". God is
described as an "author" and as possessing a "governing spirit" and without his activity there would
be nothing to perceive and all change would come to an end.

(3) God's perceptions are active rather than the mixture of passive and active perceptions given to
man. This is a problem because we can't understand perception not based on a sense-perception
model. Presumably God perceives all parts of things since his perceptions will not be relative to a
type of being. But if that is so, it leads Berkeley to realism because there will be parts of things that
we don't perceive, which he denies. A C Grayling in Berkeley The Central Argumentssuggests that
God's way of perceiving should be seen as conceiving.

(4) Berkeley actually argues at some length in Principles of Human Knowledgeagainst "abstract
ideas". He thought you cannot abstract a colour from extension by separation to achieve an abstract
idea of red, nor can you compare different shades of red to achieve an abstract idea of what red is.
An abstract triangle which is "neither oblique nor rectangle, neither equilateral" is the sort of thing
Berkeley would regard as a "manifest repugnancy".

Berkeley doesn't argue against substance, only against matter. We can have no conception of matter
because it is beyond sense and concepts are developed from experience. Substance cannot be
matter so it must be incorporeal, or spirit. I think that support for Berkeley's argument against matter
and external objects is to be found in his account of perception as outlined in Essay towards a new
Theory of Vision (this was written prior to the Principles and the Three Dialogues) in which he argues
that there is no necessary relation between visual and tactile experiences so the mind has to form
connections through various sense experiences in order to achieve the idea of things. If our
perceptions are not brought about by the fact that there is material substance an internal account in
terms of spirit is needed to explain perception.

Rachel Browne