"The point is specifically," says Sellars, "that observational knowledge of any particular fact, e.g. that this is green, presupposes that one knows general facts of the form X is a reliable svmptom of Y. And to admit this requires an abandonment of the traditional empiricist idea that obseryational knowledge 'stands on its own feet' " (p.298).

    Since Sellars says that knowledge of particular facts presupposes knowledge of general facts, such as (2), we might well wonder about the status of the knowledge of these general facts.

    With respect to knowledge itself, he neatly points out that "in characterizing an episode or a state as that of knowing, we are not giving an empirical description of that episode or state; we are placing it in the logical space of reasons, of justifying and being able to justify what one says" (pp. 298-299).

    Thus we see that Jones can justify his "knowing" of the general fact (2) for instance, i.e. that "tokens of 'This is green' are symptoms of the presence of green objects in conditions which are standard for visual perception," by citing prior particular facts as evidence, as inductive reasons (cf. p. 299); for example,

3. Tokening A of "This is green" at time t by Jones was accompanied by the presence of a green object in standard conditions of perception;
4. Tokening B of "This is green" at time t, by Jones was accompanied by the presence of a green object in standard conditions of perception; and so on.

    Sellars recognizes that some might think there is an obvious regress in this view, since, as he admits, "does it not tell us that observational knowledge at time t presupposes knowledge of the form X is a reliable symptom of Y, which presupposes prior observational knowledge, which presupposes other knowledge of the form X is a reliable symptom of Y, which presupposes still other and prior observational knowledge, and so on" (p. 298). But those who would think this are radically mistaken, he argues. He explicitly denies that any regress is involved, pointing out that while the correctness of Jones' statement that he now knows a general fact of the form X is a reliable symptom of Y (such as (2) for instance) "requires that Jones could now cite prior particular facts as evidence for the idea that these utterances are reliable indicators, it requires only that it is correct to say that Jones now knows, thus remembers, that these particular facts did obtain. It does not require that it be correct to say that at the time these facts did obtain. And the regress disappears" (p 299).

    However, while perhaps we can accept this evasion of the "temporal regress," the question still remains of how Jones can justify his knowing of the particular facts (3), (4), etc., which in turn is taken to justify his knowing the general fact (2). In other words, what about the "logical regress" here involved?

    It might be suggested that this knowledge of particular facts is self-justifying, in that it is expressed in ultimate and authoritative observation reports. But Sellars already has denied that knowledge of particular facts "stands on its own feet," and he has asserted that "knowledge of any particular fact . . . presupposes that one knows general facts of the form X is a reliable symptom of Y" (p. 298).

    Again, Sellars cannot have Jones justify his knowledge of the particular facts (3), (4), and so on, by appealing to his knowledge of the general fact (2), for this would involve him in circularity; i.e. he would be justifying his knowledge of the particular facts by his knowledge of the general fact (2), which knowledge he had initially set out to justify by his knowledge of the particular facts now in question.

    Finally, if he argues that Jones' knowledge of these particular facts presupposes other knowledge of the form X is a reliable symptom of Y (other than general fact (2) ), then even if he avoids a "temporal regress" as noted above, he is still involved in a "logical regress," in that this other general fact then presupposes logically prior knowledge of other particular facts as justification, which in turn presuppose logically prior knowledge of other general facts of the form X is a reliable symptom of Y as justification, and so on. And, it would seem, this is a , since it directly involves the issue in question: from whence stems the authority of observation reports? and how can the person who makes the report (]ones in this case) be said to know of its authority?

    Thus, since Jones cannot justify his knowledge of particular facts (3), (4), and so on as being self-authenticating without becoming embroiled in the so-called Myth of the Given, and since he can't justify his knowledge of these particular facts by his knowledge of the general fact (2) without becoming involved in circularity, and, finally, since he will fall into a "vicious logical regress" if he tries to justify his knowledge of these particular facts by knowledge of other general facts of the form X is a reliable symptom of Y -- therefore, it would seem that there is no way out, and that Sellars' proposed alternative is no improvement here at all over the much-chastised Myth of the Given.