Archives For Locke

1) Kornblith’s natural kinds are constituted by unobservable properties. This seems to have been critiqued as a return to Platonic ideals, or some kind of out-dated metaphysics, though I do not see this notion of unobservables in this light. If an unobservable is a homeostatic cluster, a gene, a chemical compound, a DNA strand, then it is induced by science to be of the physical world (metaphysics – what is the world that we may know it – in philosophy). If evolution is intoriduced to the argument, these are definitely not ideals as they are in a state of change and relationship to the environment. This is foremost a metaphysical theory (though, if it is a theory that purports to describe things in the world that can be empirically observed and tested, is it not a physical theory??)

2) There are real kinds in nature, Locke’s real essences.

3) Epistemology: this all relates to using induction to justify belief. However, always watch for using induction to justify induction. If Kornblith uses IBE about the success of science to justify induction, and IBE is a form of induction, is there a circular problem developing? I would argue that this does not need to be defined as circular, but rather that inferential inductive arguments are satisfactory so long as they are successful, as they have been thus far, until such a time as they are unsuccessful. You could take Thomas Kuhn’s paradigm shifts as a model for mapping this out. Also, watch for a priori arguments. IBE is comparative. It looks at alternative explanations, determining the best explanation for the given data. This can be used to frame the ‘satisfactory’ comment: once the data changes i.e. science is unsuccessful, induction can be argued as unjustified. However, the character of science, defined as Popper and Kuhn might put it, that it seeks to best explain the given data (explanatory, risky conjectures and refutations, and paradigmatic), science becoming ‘unsuccessful’ is highly unlikely.

4) Natural kinds and their apparent existence in the world show that inductive inference is reliable. Natural kinds can be argued for via Richard Boyd’s Homeostatic Property Cluster (HPC) account of natural kinds. The real kind structure of nature is what underlies the reliability of inductive inference. HPC is not committed to the existence of a single correct classificatory system in each scientific domain.

5) updating Locke: Locke assumed that Natural Kinds had to have all properties in common. Kornblith (in light of science) asserts that some properties are essential to natural kinds, others are non-essential, and members of natural kinds need only share the essential (HPC). Locke assumed that we couldn’t discover real essences. The advance of science has allows us now to discover ‘unobservables’. Given the success of science, or nominal kind classifications reflect real differences in kind found in nature.

6) Philosophy of science: realism vs. anti-realism. Kornblith’s argument for real kinds and the success of science reflect a traditional argument for scientific realism. Success of science is measured by empirical, explanatory, technological successes. The best explanation for this success is that scientific theories are (approximately) true and the entities they posit exist. This is IBE of an observed fact: success of science.

7) Kornblith’s view of Natural Kinds asserts that there are real divisions in nature. This runs counter to Locke who asserts that there are no chasms or gaps in nature.

8) Reductionism: special sciences reduce to physics and/or chemistry. Kornblith rejects this. Biological kinds may be composed of physical stuff, but biological kinds do not reduce to chemical or physical kinds. This seems anti-intuitive to me. I would have thought that a biological kind i.e. a reptile, would at some point reduce to a chemical kind i.e. DNA chemical makeup unique to reptiles. From Kornblith:

“Consider a particular dog, Fido. Fido is entirely physically composed … Nevertheless, even if we were to have an atom by atom description of Fido at this moment, Fido could not be identified with this collection of atoms. If we were to remove a single atom from the collection, we would not have the same collection; but we would, in all likelihood, still have the same dog.” (K, p 54 – 55)

But what if a change was made at the DNA level, at the time of conception and development of fetus, a change could be significant enough to entirely remove Fido from his natural kind grouping. So perhaps at the level of the atom kinds are indistinguishable, i.e. atoms are all alike, but at the chemical level kinds are entirely distinguishable.

Also, the question arises, am I identifiable with the matter that makes me up? Alternatively, how significant is the loss of particles and atoms in dry skin, or when I cut myself and lose blood? Do I really lose a part of myself? So perhaps there is a difference between the atoms that constitute the matter that you are, and the process of formation at the beginning, in DNA or whatever else, that determines what you are, what hair color you will have or deformities or eye color. I would have to argue that I am identical with the DNA blueprint that constitutes my physical makeup; it gives me my blue eyes, my brown hair, my height, my general physique. In this sense I argue for reductionism. But, am I identical with the atoms that come together to constitute the matter that holds me together? No. There is a temporal factor to this reductionism to do with conception and evolution.

Also, natural kinds is not about individual entities, it is about groupings.


The concept of a ‘real kind’, being a collection of unobservable properties, united in nature, jointly responsible for observable properties by which we can classify objects into kinds, is the causal structure in the world required for inductive knowledge to be possible. It is a foundation for inductive inference. Hence the importance of determining the arguments for conventionalism and realism.

Homeostatic Property Clusters:

A concept suggested by Richard Boyd: “Scientific Realism and Naturalistic Epistemology” (1981) & “Realism, Anti-Foundationalism and the Enthusiasm for Natural Kinds” (1991)

“Organisms are so structured as to maintain themselves in certain states.” (Kornblith, p35)

So homeostasis means a cluster of properties, perhaps cells, or biological systems, which work together so as to maintain themselves even the face of changes in the environment. A self maintenance program. These self-maintenance ‘parts’ are unobservables. They give rise to the salient observable properties which draw attention. For Locke, this would be the arrangement of ‘insensible’ parts.

“A natural kind is a cluster of properties which, when realized together in the same substance, work to maintain and reinforce each other, even in the face of changes in the environment.” (Kornblith, p35)

A key point to understand is that not just any arrangement of ‘parts’ is possible. By understanding the details of arrangement of insensible parts (i.e. chemistry) we understand why some arrangements are stable and others not. For instance, H2O is a possible molecule, but HO2 is not. The clustering of observable properties is a direct result of configurations which are possible at the unobservable level. This is the path to explaining what it is about the world that makes it knowable.

“Because there are natural kinds, and thus clusters of properties which reside in homeostatic relationships, we may reliably infer the presence of some of these properties from the presence of others. In short, natural kinds make inductive inference possible…” (Kornblith, p36)

A problem arises:

Remember that in nature we have real kinds, and nominal kinds. Real kinds correspond to homeostatic clusters of unobservables, and nominal kinds are the abstract Idea to which the real kind/essence is attached. However, invoking philosophy of science and turning to unobservables, the question arises whether they are real properties in nature or merely nominal. Therefore we need an account for which unobservable, homeostatic clusters are real, and not nominal. Therefore the argument is postponed by homeostatic clusters, and not concluded.

Kornblith does not worry about such objections:

“Were the postulation of such underlying properties and relationships unrelated to the predictive, explanatory and technological successes of science, there would indeed be reason to think that appealing to such unobservables is nothing more than a sham. But in light of the intimate relationship between the postulation of unobservable structure and the various successes of science, one can no longer reasonably doubt the real existence of such structures.” (Kornblith, p41)


Kornblith suggests that the success of science is the direct result of the postulation of unobservable structure that underlies appearances (essence).

Kornblith finds three contrasting views sitting side by side in Book III of An Essay Concerning Human Understanding (Locke). He sees this as a great strength in Locke as Locke was struggling with his reason and empiricism and certain intuitions that did not necessarily add up. With regard to natural kinds Kornblith asserts that these seeming contradictions are problems for us all; they are universal contradictions which pull us in different directions on this issue. These three views are broadly Kornblith’s own interpretation of Locke, and direct reference to their presence in the text is not made. This is a window to the larger, more contemporary discussion.

The key question: are there real kinds in nature? or do we (humans) impose them on nature for the benefit of our own understanding?

1) Conventionalist: no real kinds in nature. This is appealing as it lumps the burden of proof to the realist. Though ultimately, it seems a bit hard to swallow once you update the conversation to include evolution, chemistry, biology etc.

2) There may be real kinds in nature, but what they are is unknowable by us (locke’s official position): this seems to me to be like the worm trying to perceive the elephant. This is also a particularly British empiricist view.

3) There are real kinds in nature and what they are can be known by us. This is known as corpuscularianism. This is realism.

Two Arguments for Conventionalism:

This is an analysis of Book III, chpt vi of Locke’s Essay. It seems to be essentially a linguistic argument, pre-linguistics. Locke discusses how a word is capable of referring to kinds of things i.e. a signifier (word – cat), signified (kind – cat) and referent (an actual cat).

The question of whether something is or is not a cat just amounts to the question of whether it does or does not answer to the idea one associates with the term ‘cat’.” (Kornblith, p18)

This seems simple enough. Locke, however, being pre-Nietzsche and pre the proper onslaught of scientific industry and culture relates these connections to metaphysical concepts:

“The measure and boundary of each Sort, or Species, whereby it is constituted that particular Sort, and distinguished from others, is that we call its Essence, which is nothing but that abstract Idea to which the Name is annexed: So that every thing contained in that Idea, is essential to that Sort.” (III, vi, 2)

Such an apparent linguistic argument seems to invoke much later philosophical thought such as that of Derrida’s differance and drift let alone any conflicts with scientific realism. This raises the interesting question of how to read linguistic or hermeneutic philosophy with regard to scientific realism. Where do they cross over, are they at odds (of course different views from different philosophers produce different contrasts). Never-the-less, this is Locke’s picture of conventionalism. One key argument he makes is a priori, the other empirical:

a priori – the essential properties of an object derive not from features of the object itself, but only from the idea associated with soem term used to pick it out. No empirical facts are called upon for this argument.

empirical – (pre-evolutionary biology, or plain modern biology) ‘irregular and monstrous births’ observed in animals give us reason to doubt whether Nature designs things by reference to a model; a regulated, established essence. Also, there are no great chasms or gaps in Nature. Rather, things differ from one another by a series of small steps. Instances might be birds that live on the ground, fishes that have wings, sea creatures that inhabit the land etc.

Essentially, modern science makes it easy to reject these sets of arguments for conventionalism. At what point does the categorization of beings stop? For instance, all animals (incl. humans) could be in the Kind named ‘built from DNA’ which would most definitely have to be an essence and therefore a negation of conventionalism.

Kornblith sees the study of these two arguments as essential. Locke himself did not fully explore the relationship of these two arguments or recognize questions that they seem to bring to the fore. Namely: our traditional taxonomy, whether there are gaps between its groupings or instead merely differences of degree – whether our taxonomy is the only possible taxonomy, or whether it is, instead, merely one among many.

As to why these questions remain important in this context, in light of scientific realism and modern advances in science and philosophy, I am not yet sure.

Chapter 3 response:

Kornblith responds to the a priori argument, being a conceptual argument, by widening the scope and introducing an empirical dimension.

“It seems to me, however, that the argument is better understood as an inference to an explanation: the idea that some properties are essential to a kind and others are not can be fully explained by way of our conceptual activity, and no other explanation seems even possible. Essential properties are thus best explained as merely a product of the way we think about the world, and there is nothing to be gained by postulating the existence of real kinds. When put in these terms, the argument does not appear to be a conceptual argument at all, and it may be defeated by offering empirical considerations which would suggest an alternative explanation of the apparent existence of essential properties of kinds.” (Kornblith, p46)

He is of course referring to advances and successes in science since the time of Locke.

“Natural Kinds” Philosophy 63 (1988) pp 29 – 42

The problem of Natural Kinds is that there is no agreement anywhere about a doctrine for how to determine natural kinds. Certain paradigm examples have agreement: the kinds oak, stickleback and gold are natural kinds, and the kinds table, nation, and banknote are not. Wilkinson identifies two conditions which must be fulfilled to categorize a natural kind:

1) the notion of a natural kind must be tied to that of real essence.

2) 2) members of natural kinds, and the corresponding real essences, lend themselves to scientific investigation.

Natural kind predicates are also inductively predictable. It is easy to predict the behavior of the lump of stuff in front of me if I am able to determine it is oak. Alternatively, it is impossible to inductively predict the behavior of a nation. Also, any single object/entity might belong to one natural kind and numerous non-natural kinds. This does not effect the concept of inductive predictability as you are making your inductive predictions based on membership to a natural kind.

Distinguishing Between Natural Kinds and Non-Natural Kinds

A natural kind relates directly to the science that studies the real essence. For instance, ‘clouds’ do not have real essence, thereby a meteorologist does not study a real essence as such. Gases and water vapor do have real essence and so the chemist studies more precisely the natural kind. Likewise, a geographer or geologist might study a cliff, but the cliff does not have real essence. Instead it is the rock or granite, the realm of the physicist/chemist. See Locke on real and nominal essences.

The normative account: is it possible for anything naturalistic in character to have normative value?

Locke’s real and nominal essences are used to discuss natural kinds. Locke’s view on natural kinds shoots in three seperate directions: conventionalist (classification convenient and not accurate) , realist ‘light’ (Locke’s official position; that there are real kinds, though real essences unknowable), and realist (kinds are known with difficulty).

Realism: there are individual things in nature. There are also real kinds of things. They exist, and hence we can discover them. We do not construct them or imagine them. They are real divisions found in nature. Kornblith points out that create categories, which can be accurate/inaccurate or useful/not-useful, but there are real divisions. Such as mammals, further divided into cats and dogs, and into ever smaller categories. Conventionalism suggests that individual things in the world are real, but kinds are not. Categories are a human construct. The classification system is all important.

Notes from the Stanford Encyclopedia

Locke’s philosophy of epistemology is the foundation of his philosophy of science. Being a philosopher of the enlightenment his epistemology is metaphysical, though he took large strides to create a philosophical grounding for the experimental science of the day.

And if he is a devotee of the new science, he often appears an uncertain one, recognizing profound difficulties in it. In consequence, Locke’s work is characterized by tensions and nuances…

On the one hand Locke retains an ideal that all knowledge is demonstrative and certain. A view shared with the Aristotelian’s and Cartesian’s. On the other hand, impressed with empirical methods, he defines a distinct kind of knowledge, one inferior to genuine scientific knowledge but appropriate to human sensory capacities.Locke inherited the philosophical conception of scientia which has roots in Aristotle. Scientia proposes that scientific knowledge is certain knowledge of necessary truths, which can in principle be expressed in syllogistic form, the conclusion following from self-evident premises (deductive). Locke develops the concept of scientia by distinguishing 3 separate kinds of knowledge: intuitive, demonstrative, sensitive.

Intuitive knowledge is the most certain because the truth is grasped immediately. There are no intermediate steps, and doubt is impossible because the mind can no more avoid recognizing the truth than the open, functioning eye could avoid seeing light when turned toward the sun (E See IV.ii.1, p. 531). Demonstrative knowledge, though also qualifying as certain, is less so because it involves intermediate steps. We cannot grasp immediately that the three angles of any triangle are equal to two right triangles, and must instead construct the steps of a proof.

Locke’s objects of scientia: real essences and the necessary conditions that flow from them (causality?). Locke then distinguishes between real essences and nominal essences. The real essence is that which makes the thing what it is, and the nominal essence consists in the set of observable qualities we use to classify a thing (may change over time).

We have scientific knowledge of something when we know its real essence and, since its qualities flow from that real essence, when we know the necessary connections between the essence and its other qualities. Geometry serves as an exemplar, as it did for so many of Locke’s predecessors. In knowing what a triangle is, we cannot conceive things being otherwise than that the sum of its three angles equal the sum of two right angles.

Real essences are impossible for the human being to know, due to the constraints of sense data. Therefore the epistemological question of knowledge needs to be addressed. Locke rejects skepticism. Instead he lowers the bar for what defines knowledge, invoking another kind of knowledge, one which is not certain; sensitive knowledge. This is knowledge of effects that have come to our senses, without us determining or developing an understanding of their cause. Sensitive knowledge does not get to understand real essences, instead it knows only those perceived properties from which we construct nominal essences. Experience.

Has contemporary science enabled us to go beyond sensitive knowledge—have discoveries about compounds, elements, and subatomic particles provided us with knowledge of real essences? Much of the force of this question derives, to paraphrase Nicholas Jolley, from the fact that many of those discoveries about matter’s structure were not conceived empirically, but only confirmed empirically; they were initially conceived as possibilities by employing the hypothetico-deductive model, and the predictions deduced from the models were then compared to empirical data (Jolley 2002, p. 69). Yet as Jolley also points out, these commentators may have missed the full import of Locke’s geometric model; in a passage quoted earlier, Locke tells us explicitly that if we knew the real essence of gold, we could deduce its qualities even if gold did not exist.