Chapter 1
Assumption of realism
“Scientific realism posits a world that is structured by its division into natural kinds independently of any investigation,
whose structure and behaviour is a stable, theory independent object of inquiry and accumulating knowledge.” (p. 10).
And:
“Scientific realism also makes a claim about explanation: that successful explanations warrant belief in the entities and
structures posited by those explanations.” (p. 10).
in order to support realism, Hendry needs to say something about reference of theoretical terms. (Kuhn’s assumption of
descriptivism; Kripke/Putnam causal theory as a response to threat of incommensurability). Argues this in part I (chapters 1-4).

Key point will be that reference is constant across theory change—a key constituent of scientific realism (arguably
required for a meaningful notion of progress)
Choice between emergence or reduction.
Familiar from philosophy of mind literature
A properties/events/facts supervene on B properties.... Something must explain this correlation. (pp. 11-12).
Possible explananda, according to Hendry: Either (i) facts about us (some sort of anti-realism—rationality constraints, e.g.
irrational to judge that x and y differ in beauty if they do not differ physically), (ii) downwards causation (“A pushes B around”—
emergence) or (iii) causal closure (“B pushes A around”—reduction/elimination).

I don’t think this is quite right: (ii) and (iii) don’t look like explanations of supervenience to me. Broad’s emergentism,
for instance, required trans-ordinal laws to explain supervenience; functionalists cite realization, not causal closure.

But it’s easy to agree that realist supervenience theories force a choice between emergence and reduction—Hendry will
go for emergence.
Chapter 2
On the causal theory of reference, its essential commitments and various theses associated with it.
Descriptivism
Ramsey-Lewis account of theoretical terms—‘charge’ = the unique actual occupant of a certain theoretical role within theory T.
Meanings given by theoretical content. Knowing the meaning of a kind term is knowing a set of descriptions sufficient to identify
members of the kind. C.f descriptive names: Aristotle =df the Greek philosopher who wrote the Nicomachean Ethics
Problems for descriptivism:

Unwanted necessities/a priorities. (c.f. Kripke on names)
“Firstly, if to be gold is by definition to be yellow, malleable, ductile, of high density, metallic and resistant to chemical
reaction, then ‘gold is resistant to chemical reaction’ is true by definition, just like ‘all bachelors are unmarried.’ But is it
really impossible that scientists could discover a new form of gold that is highly chemically reactive? If not, then being
resistant to chemical reaction cannot be a necessary property of gold.” (p.16).
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
How can terms in successor theories refer to same entities as corresponding terms in the theories they replace? Without
sameness of reference, there is (arguably) no scientific progress. [Compare: Vikings thought that stars were light shining
through holes in the skull of a dead giant. For descriptivists, does it make sense to say they were wrong about stars?]

Further Kripkean argument: most people are ignorant of the theoretical descriptions associated with scientific terms. (It
isn’t the case that we all associate the same descriptions with ‘Aristotle’; not preserved during learning.)
Causal Theory
Meaning is reference, and is fixed by ostension. Point at a sample of water, and baptise it—I stipulate that anything bearing the
same-liquid-as (or perhaps same substance-as) relation to that stuff, shall be known under the name ‘water’. (Putnam)

Putnam is a microstructuralist—to bear the same-liquid-as relation to that sample of water is to share its microstructural
properties, whatever they might be.

Descriptive version: ‘water’ =df anything that bears the (microstructural) same-liquid-as relation to the colourless stuff
that falls from the sky around here

Nice feature: you don’t have to be right about the nature of the substance ostended to succeed in referring to it. x and y
do not have to agree about the nature of gold, water etc. to refer to the same substances with their terms.
Claims associated with the causal theory
Hendry says that the causal theory is associated with claims about: (i) naming of kinds by picking out samples, (ii) semantic
externalism, (iii) causal connections between users of names and kind samples, (iv) essentialism, (v) microstructural individuation
of chemical kinds, (vi) physical reduction of chemical kinds (pp. 18-19).

Hendry: only claims (i) and (ii) are necessary if the causal theory is to secure continuity of reference across theory
change (hence supporting realism).
(i) Sameness of kind and the ‘qua’ problem for the causal theory
Particular samples of a given kind will differ in all sort of ways (temperature, purity, phase...). We want ‘gold’ to apply to all
samples of gold, regardless of such differences, but how is this determined by the intention of the Baptist? In other words, “qua
sample of what is the sample named, and how is this determined by the intentions of those who introduce the name?” (p.19).

Example: ‘oxygen’ applies not only to gaseous, but also solid and liquid oxygen; to different isotopes of oxygen.
According to IUPAC definition, ‘oxygen’ applies to anything with a nuclear charge of +8 (8 protons in the nucleus)

How could Lavoisier have intended reference to anything with atomic number 8 when naming gaseous oxygen?
A further issue: Putnam assumes that sameness of kind relations are equivalence relations, but it is not a priori that they are
transitive. Seems we would need to know just what sort of same-liquid-as relation we latch onto in the world in order to know that
the extension of ‘water’ is an equivalence class under that relation.
Point: we need to attribute to historical scientists conceptual apparatus to pick out sameness of atomic number relation, but it’s not
obvious how they could have done so. Hendry is going to postpone discussion of this matter to chapters (4) and (5).
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(ii) Semantic externalism
Putnam’s famous twin-Earth thought-experiment. In Putnam’s original paper, the argument is somewhat convoluted. Something
like this: reference doesn’t supervene on the intrinsic properties of speakers (this is what twin-Earth is supposed to show), so
either (a) meaning doesn’t determine reference, or (b) meanings aren’t “in the head”—i.e. don’t supervene on intrinsic properties
of speakers either. Putnam prefers to reject (a)—in common with the descriptivist theories he is arguing against—and hold (b).
More natural way of interpreting it: meaning of natural kind terms just is reference (c.f. Kripke on names) so neither meaning nor
reference is fixed by “what’s in the head”.

Note that this thesis extends in a fairly intuitive way to propositional attitudes, at least if you think that their contents are
the truth-conditions of embedded sentences

Hendry doesn’t need to go that far—continuity of reference is secured as long as the reference of theoretical terms is
independent of the beliefs of speakers, whatever the contents of their propositional attitudes might be.
(iii) Causal theory of reference
Hendry: nothing causal about reference, because when we baptise water ‘water’ this action i caused by our semantic intentions,
not by the sample itself.

Causation is only needed to pass reference on to others, and is part of what explains how reference can be deferential—
we can refer to e.g. electrons without having any idea how to identify them, or any true beliefs about their properties
I don’t think this is quite right. In order to baptise water ‘water’, don’t I need something like a perceptual demonstrative? “I
hereby baptise that substance ‘water’. That seems to me to implicate causality in the explanation of reference even for the Baptist.
(iv) Essentialism
General point about the relationship between semantics, modality and essence. The semantic theory gives us at best necessary
connections between the term ‘water’ and H2O. [Roughly, the causal theory implies that necessarily, everything in the extension
of ‘water’ is H2O—on the assumption that sameness of substance implies sameness of microstructure.]

Familiar from Fine’s work that not all necessary properties are essential—classic example is Socrates and {Socrates}

Too quick to read off that water is essentially H2O from the fact that necessarily, if something is water then it is H2O.
How then should we choose between candidate essential properties (all of which are presumably necessary)?
“However, this doesn’t show that atomic number, ground-state electronic structure and spectroscopic behaviour are all on
a par as candidate essences. The first point to make is that, given relevant laws of nature—quantum mechanics, the
exclusion principle—nuclear charge determines and explains electronic structure and spectroscopic behaviour, insofar as
that behaviour is determined, but not vice versa. Nuclear charge (and therefore atomic number) is privileged by its
asymmetric relationship of nomic determination to these other properties.” (p.25)
A further suggested argument for microstructural essentialism: perhaps something might be made of the fact that ‘water is H2O’
seems to be metaphysically necessary, whereas candidate macro essential properties—liquidity at 20C etc.—seem only nomically
associated with water? But (i) many deny that there is a distinction between nomic and metaphysical necessity, and (ii) as Hendry
points out (pp. 26-7), it looks question begging.
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
General point here is that the causal semantics (arguably) needed for realism only gets us as far as modality, but further
commitments are needed to get us from there to essentialism of any kind.
(v) Microstructuralism
Sameness of kind/substance relations implicated in the causal theory need not be microstructural. [DY: is microstructuralism the
microstructural essentialism (top of p. 27) or not? If so, hasn’t Hendry already rejected it a fortiori by rejecting essentialism?]

Hendry: the causal theory makes macroscopic sameness of substance relations possible as well as microstructural ones.

“Gold is the substance that bears the no-entropy-of-mixing relation to this. (pp.27-8)
Hendry will argue for microstructuralism over the course of chapters 3 and 4. [But will he argue that substances have
microstructural essences, or just that ‘being the same kind as’ requires microstructural qualitative identity?]
(vi) Reduction or autonomy of chemical kinds
Microstructuralism not committed to reductionism, says Hendry—consistent to hold that being the same substance as water is
being H2O, and that special causal laws govern the behaviour of H2O molecules, which are not deducible from more basic laws.

See A. Beckermann, ‘Supervenience, Emergence and Reduction’ (posted on group webpage) for a very useful discussion
of the concept of emergence.
Alexander’s dictum (as interpreted by Hendry, pp. 28-9): unless a property of some complex particular ‘makes a causal
difference’, we should regard it as in some sense nothing over and above the properties of its parts. (c.f. mass)

I don’t think difference-making is the right notion here. In recent literature on mental causation, difference-making is
interpreted counterfactually. Digression...
Suppose that A makes a difference to B iff (i) had A not happened, B would not have happened, and (ii) had A happened, B would
have happened (Block semantics, not Lewis). On this view, your desire to ring the doorbell makes a difference to your ringing it,
but the precise neural realization of your desire does not. But this is not emergentism!
More on the qua problem
LaPorte’s example of the stay at home vs. travelling scientists seems to show that whether a substance counts as a distinct natural
kind or a variant of an existing one is a matter of decision rather than discovery.

Problem of too many kinds (isotopic variation)

We need there to be a fact of the matter (if we are to avoid some form of conventionalism) about whether heavy water is
in the extension of ‘water’, and we need this fact to have been determined by the intentions of scientist who didn’t know
that heavy water existed.

Hendry is going to tell a story to make this plausible in chapters 3 and 4.
DY
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