Criteria of identity

Observations must be public in that they must be replicable by any properly trained observer. The experienced conditions that led to the report of certain experiences must be described in sufficient detail that others can duplicate them and consequently have experiences that meet criteria of identically. That someone else may set up similar conditions but not have the same experiences proves that the original investigator gave an incorrect description of the conditions and observations, or that he was not aware of certain essential aspects of the conditions. 

Critical limitations are those determining the separation and identification of spots. If a spot remains unresolved in three different solvent systems, it may be considered homogeneous. If its position coincides in these solvent systems with that of a known, run simultaneously, its identity is then considered established. These criteria should, however, be buttressed by as many other criteria of identity as are available, such as highly specific color tests, chemical alteration, or better still, where possible, isolation of the material in quantity sufficient to permit employment of classical identification methods. That there is need for these further criteria was shown by Levine and Chargaff,212 who noted that l-amino-2-hydroxypropane and 2-amino-l-hydroxypropane have the same Rf values in five different solvent systems. 

The interesting question concerns the justifications within the subset, the justifications of simple sentences which fix the reference of words and thereby constitute the structure of reality. Can sentences like This is a dog be justified and yet false Yes, in two different ways. The first way is when the justification procedure is not executed properly. I may fall victim to an illusion, or I may be too careless. I may then believe that the justification conditions are satisfied, but they are not. In a weak sense, I have justification, but my justified view is wrong. This does not present a difficulty for the view summarized in Figure 2, which maintains that the criteria of identity of entities are identical with justification conditions. One may misjudge whether a justification condition is satisfied. But this does not change the justification condition. Of course, a justification condition should be such that it can be easily and uncontroversially settled whether it is satisfied. (Otherwise it would not be a justification condition.) But it would be far too much to demand that no mistake should be possible about it. If the justification conditions are not affected by the occasional mistakes, they may fix the reference of words and provide criteria of identity. The occasional mistakes just do not matter. 

IR3) is the thesis which distinguishes internal realism from the doctrines it is most closely related to. Kant would have endorsed some version of (IR1). Peirce would have accepted (IR2) as well. But the sort of conceptual pluralism (IR3) represents has not traditionally been part of the picture that reality and truth are not independent of the human mind. We must start approaching this thesis from a distance. We already know that a conceptual scheme is a relatively self-contained group of words or concepts. The referents of the words that make up conceptual schemes are determined by the justification conditions of some simple sentences in which they occur. So we may also say that a conceptual scheme is the set of justification conditions for a set of sentences. The determination of reference is the same as the constitution of the structure of reality, because the entities - individuals, kinds, etc. - are carved out by justification conditions which provide criteria of identity for them. So the structure of reality is constituted by conceptual schemes. 

This tacit commitment to (IR1) shows that the internal realist account of reference is indeed a species of the anti-realist answer to the skeptical challenge. The challenge, posed by Putnam s model-theoretic argument was this. If the structure of the world were independent of the human mind, how could concepts and words, which are human inventions, refer to the elements of the structure The answer provided here is that the structure of the world is not independent of the mind. The criteria of identity for entities derive from the justification conditions which govern the use of concepts. So the entities out there and the entities our words are intended to apply to are bound to be the same. We should not be surprised that the top slices meet the bottom slices. We just slice from the top and reach the bottom. 

This is somewhat similar to Wittgenstein s view in On Certainty. Wittgenstein emphasizes there are some empirical propositions we cannot doubt, because doubting them would call into doubt the meaning of our words, e.g. I am no more certain of the meaning of my words than I am certain of certain judgments. Can I doubt that this color is called blue ( 126. See also 80, 81, 114, 124, 140). Of course, he would reject the philosophical speculations about the structure of reality, criteria of identity and the like. 

Molecular and atomic spectra play an important part in Mulliken s view of the nature of chemical beings (Mulliken 1932). How do we set up an experiment to produce molecular affordances Why is it illegitimate to project electron affordances back as constituents of atoms, but legitimate to project atom affordances back as constituents of molecules The short answer is simply that there are clear criteria of identity, both numerical and qualitative, that serve to pick out atoms as material individuals. The metaphysical question was settled empirically by the development of the technique of the travelling tunnelling microscope for which Binnig and Rohrer (1986) were awarded the Nobel Prize. The shape and boundary of an individual atom could be traced out. Is there a corresponding procedure that would establish electrons as bounded individuals ... 

Modality as necessity can usefully be captured in the intuition that the statement in question cannot intelligibly be negated. This intuition can reflect two very different kinds of beliefs or presumptions as to what the function of the law statement could be. R may be that those who hold to the law believe that there is a stable natural mechanism that accounts for the regularity covered by it, as a matter of empirical fact. However, some universal statements are taken to be necessary because their function is not to describe the ways things must be with a pre-given vocabulary, but rather to express a rule which fixes some aspect of the meaning of the descriptive terms that appear in the law . It may be that the law only seems to be about material stuff in the material world. It expresses a semantic rule rather than a putative matter of fact. Newton s Second Law, that the force acting on a body is the product of mass and acceleration, has sometimes been treated as a definition of force as that which produces acceleration. Frederick Waismann once declared that all statements ever uttered by chemists, except the most recent, were necessary truths, since they served to amplify the criteria of identity for the substances in question. 

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