by Daniel A. Kaufman
As these prolegomena begin to wind down, I want to step back and speak a bit more generally about the conception of philosophy – and of inquiry more generally — from which they spring. Sellars, of course, in the opening paragraphs of “Philosophy and the Scientific Image of Man,” gave his own account of what he takes philosophy to be doing:
The aim of philosophy, abstractly formulated, is to understand how things in the broadest possible sense of the term hang together in the broadest possible sense of the term. Under ‘things in the broadest possible sense’ I include such radically different items as not only ‘cabbages and kings’, but numbers and duties, possibilities and finger snaps, aesthetic experience and death. 
I largely agree but want to be more explicit. Philosophy…
(a) describes and analyzes the logics, grammars, ontologies, and epistemologies of the different types of discourses/investigations/forms of life in which we engage, and
(b) endeavors to develop a framework within which these all can be understood as pictures of/activities within/lives belonging to a single world.
It is important to emphasize that philosophy is form of inquiry that takes place from within the Manifest Image. It considers the world as it is, including persons, their representations, points of view, and values, and when it engages with science, it does so with the aim of rendering its investigations and results intelligible from a human point of view and with regard to human interests. As Massimo Pigliucci and I have discussed, scientific investigation is an activity that people engage in, which is why its essentially quantitative content appears within a narrational, qualitatively inflected frame. A truly “perspectiveless” science, if such a thing were even imaginable, would consist of nothing but statistics.
The Scientific Image aims at as perspectiveless a perspective as possible, by limiting its investigations to that which can be observed, in a highly disciplined way, from a third-person point of view and by restricting its scope to the study of quantifiable magnitudes. This is why between the two, the Scientific Image represents a greater degree of abstraction than the Manifest Image and is methodologically dependent upon it, as Sellars explains:
There are as many scientific images of man as there are sciences which have something to say about man. Thus, there is man as he appears to the theoretical physicist — a swirl of physical particles, forces, and fields. There is man as he appears to the biochemist, to the physiologist, to the behaviourist, to the social scientist; and all of these images are to be contrasted with man as he appears to himself in sophisticated common sense, the manifest image which even today contains most of what he knows about himself at the properly human level. Thus the conception of the scientific or postulational image is an idealization in the sense that it is a conception of an integration of a manifold of images, each of which is the application to man of a framework of concepts which have a certain autonomy…Thus ‘the’ scientific image is a construct from a number of images, each of which is supported by the manifest world.
The fact that each theoretical image is a construction on a foundation provided by the manifest image, and in this methodological sense pre-supposes the manifest image…
It is because philosophy belongs to the Manifest Image that the basic conditions of adequacy for philosophical theories lie in ordinary experience and language – what in philosophy is called “common sense”  – and I want to suggest that the Scientific Image’s dependence on the Manifest means that the same is ultimately true of it as well. It is in acknowledgment of this that the late (and very great) Stanley Rosen wrote the following [my emphasis]:
My thesis is not simply that there is an ordinary language, reflective of the common stratum of human nature… I also claim that this ordinary language is retained as a basis… of all technical dialects. It is this basis that serves as the fundamental paradigm for the plausibility or implausibility of theoretical discourse and particularly of philosophical doctrines. It is not satisfactory to evaluate philosophical doctrines on a purely technical or formal level because these grounds cannot establish their own validity or authority… 
It is important to remember that by ‘conditions of adequacy’ we do not imply or suggest that the elements of common sense (meaning, again, ordinary experience and language) constitute epistemic foundations or that they are infallible, indubitable, certain, etc. They do not and are not. Rather, they represent the conditions under which the relevant inquiry or activity takes place and sometimes even its very subject matter and consequently function as constraints on what count as acceptable theories.
This is perhaps easiest to see in ethical and aesthetic theorizing. As W.D. Ross observed, the feelings of obligation that we already have provide the subject-matter and motivation for moral theorizing, just as our experiences of beauty and ugliness provide the subject-matter and motivation for aesthetic theorizing. And just as no aesthetic theory could never ultimately override my experiencing of something as beautiful, no moral theory can ever ultimately override a feeling of obligation.  This does not mean that either our experiences of beauty of obligation are never incorrect or that we never can change our minds with regard to such things but rather that our experiences of beauty and feelings of obligation constitute the ultimate arbiter. This is why virtually every objection to a moral theory aside from those concerned with matters of internal consistency involves pointing out some way in which the theory contradicts the moral intuitions we already have in one way or another.
It is worth noting that we can say much the same about scientific theorizing. It is motivated by and its subject matter consists of that which we observe and experience in the world. Of course, these observations and experiences are not certain and do not constitute epistemic foundations, but rather are fallible and may be revealed as being illusory. Nonetheless, they constitute the ultimate conditions of adequacy for any scientific theory: bogus experiences and observations are ultimately revealed by better ones, not by theories, and no theory or element therein stands outside the jurisdiction of observation and experience.  As Quine famously pointed out, even the most seemingly unmovable principles may be contradicted, given a sufficient confrontation with experience.
The totality of our so-called knowledge or beliefs, from the most casual matters of geography and history to the profoundest laws of atomic physics or even of pure mathematics and logic, is a man-made fabric which impinges on experience only along the edges. Or, to change the figure, total science is like a field of force whose boundary conditions are experience. A conflict with experience at the periphery occasions readjustments in the interior of the field. Truth values have to be redistributed over some of our statements.
Any statement can be held true come what may, if we make drastic enough adjustments elsewhere in the system. Even a statement very close to the periphery can be held true in the face of recalcitrant experience by pleading hallucination or by amending certain statements of the kind called logical laws. Conversely, by the same token, no statement is immune to revision. 
Human beings are, as far as we know, the only creatures who theorize and more broadly, engage in epistemic activities. Inquiry begins from and ultimately takes as its subject matter that which falls under the purview of human experience and is articulable in human language which means that at the end of the day, human experience and language impose the basic conditions of adequacy on all inquiry. Philosophy makes a fundamental mistake when it conceives not just of what it does, but what any inquiry does, as being in any way transcendent or as involving transcendent principles. In “The Human Prejudice,” Bernard Williams observed that —
It is a muddle between thinking that our activities fail some test of cosmic signiﬁcance, and (as contrasted with that) recognizing that there is no such test. If there is no such thing as the cosmic point of view, if the idea of absolute importance in the scheme of things is an illusion, a relic of a world not yet thoroughly disenchanted, then there is no other point of view except ours in which our activities can have or lack a signiﬁcance. 
— and I would maintain that the same is true epistemically. So, just as Peter Singer is mistaken in believing that the principle of utility represents some disinterested, demonstrable, neutral principle that is part of some independent moral reality, when in fact it is an expression of human experience and interests, so we are mistaken in thinking that theorizing of any kind operates outside of or transcends or otherwise escapes human experience and language.
 I say this in order to distinguish the sense of ‘common sense’ as it is used in philosophy from its use as meaning “horse sense.”
 Stanley Rosen, Metaphysics in Ordinary Language (New Haven: Yale University Press, 1999), pp. 227-228.
 W.D. Ross, The Right and the Good (1930), p. 40.
 Ibid., pp. 40-41.
 W.V.O. Quine, “Two Dogmas of Empiricism,” The Philosophical Review 60 (1951), Section VI, ¶2.
 Bernard Williams, Philosophy as a Humanistic Discipline (Princeton: Princeton University Press, 2005), p. 137.