The last quotation suggests why such indubitable propositions constitute a world-view. Wittgenstein holds that unlike theoretical premises, they do not stand alone, as matters of logic proper, but rather together: “It is not single axioms that strike me as obvious, it is a system in which consequences and premises give one another mutual support” (1972: § 142). “When we first begin to believe anything, what we believe is not a single proposition, it is a whole system of propositions. (Light dawns gradually over the whole)” (ibid.: § 141). Wittgenstein describes how this holistic learning takes place as follows (ibid.): “I am told, for example, that someone climbed this mountain many years ago. Do I always enquire into the reliability of the teller of this story, and whether the mountain did exist years ago? A child learns there are reliable and unreliable informants much later than it learns facts which are told it. It doesn't learn at all that that mountain has existed for a long time: that is, the question whether it is so doesn't arise at all. It swallows this consequence down, so to speak, together with what it learns.”
The holism of synthetic a priori propositions helps us to understand how such groundless propositions can “stand fast.” They are of course taken for granted, which means that normally they do not dwell in the light of consciousness and therefore are not open to question (as Wittgenstein says, some propositions are simply swallowed down together with what is learned). But there is more to this kind of pre-epistemological security. Because they are all tied together, these propositions are continually rein-forced by all the other such propositions, in the sense that to question any is implicitly to question many, if not all. And since together they constitute one's world picture, that is, the picture according to which one goes about the activities of one's everyday, ordinary life (standing up, sitting down, going from one place to another, etc.), such questioning tends to pull the very ground from beneath one's feet. It is for this reason that Wittgenstein tells us that what holds these propositions fast is the movement around them (1972: § 114): “The child learns to believe a host of things. I.e., it learns to act according to these beliefs. Bit by bit there forms a system of what is believed, and in that system some things stand unshakably fast and some are more or less liable to shift. What stands fast does so, not because it is intrinsically obvious or convincing; it is rather held fast by what lies around it.” Such propositions are groundless, then, because they themselves constitute the ground. And like any ground or horizon, they are fixed only relative to their correlative figure or theme, which in the present case amounts to one's everyday, precognitive practices.6
Gier (1981: chap. 8) finds that Wittgenstein distinguished two sorts of such synthetic a priori propositions, one having to do with grammatical rules and another that is a question of facts rather than rules. For example, “I cannot remember the future” runs contrary to certain fundamental Western understandings because it fails to adhere to the grammatical rules of usage. The proposition makes no sense since it defies the logic of grammatical convention rather than empirical fact: we simply do not use ‘remember’ in this way, to take as its object the future. But the proposition “I have only one body” is not a question of rules of usage; instead, it is bound up with empirical matters of fact.
Despite the difference between them, however, both kinds of proposition run irremediably between the analytic and the synthetic. Grammatical propositions constitute the logic of a language and the basis on which people act and make meaning. In this sense, they are a priori and enjoy an analytic nature. But plainly, as ‘rules’ of grammar, even if implicit ones, they are also subject to the material process of history and are thus synthetic. Hence, they obtain halfway between the formal and the factual or contingent. The other sort of a priori propositions have the form of ordinary empirical propositions but enjoy a special ontological status. “It is clear that our empirical propositions do not all have the same status,” says Wittgenstein (1972: § 167), “since one can lay down such a proposition and turn it from an empirical proposition into a norm of description.” By “norm of description,” Wittgenstein intends a proposition that “gives our way of looking at things, and our researches, their form. Perhaps it was once disputed. But perhaps, for unthinkable ages, it has belonged to the scaffolding of our thoughts. (Every human being has parents.)” (ibid.: § 211). Such presuppositions are bound up, not with rules of usage, but with the way things are and what there is. They serve as pinions of reality, and, in this sense, may be thought of as analytic or even transcendental. But Wittgenstein's characterization of them as empirical propositions transformed into norms of description suggests that they too are synthetic in nature. Moreover, just as, like any rules, the rules of grammar are subject to change, so such hard propositions can lose their special status among empirical propositions. For example, whereas we have ordinarily always presupposed that every human being has two, and only two, parents, with the invention of the technology of surrogate motherhood, whereby the biological processes of ovulation and gestation are divided between two women, is it not the case that now some children may be said to have not two but three parents?7
Although on the surface of it, there do seem to be differences between grammatical and hard propositions, it is not clear to me that they are fundamentally different. Gier himself (1981: 175) suggests that the appearance of the distinction in Wittgenstein's work “reveals some possible confusion in Wittgenstein's thinking.” I have brought Gier's discussion to bear here because it is exceedingly helpful in clarifying Wittgenstein's focus on the question of the a priori. For my purposes, what is important to see is that both grammatical and hard propositions constitute synthetic a priori. As such, neither is normally a question of truth or falsity; rather, both embody the conditions for determining what is true and what is false. In addition, both confound the distinctions between the analytic and the synthetic, or reason and fact, such that these distinctions are rendered essentially fuzzy and less than fast.
Merleau-Ponty
In his monumental work, Phenomenology of Perception, Maurice Merleau-Ponty takes Kant to task for failing to follow out his own program, “which was to define our cognitive powers in terms of our factual condition” (1962: 220–21). Had Kant done so, finds Merleau-Ponty, he would have arrived at “a new definition of the a priori” (ibid.: 220), in which the a priori is no longer cleanly distinguishable from the a posteriori: “From the moment that experience—that is, the opening on to our de facto world—is recognized as the beginning of knowledge, there is no longer any way of distinguishing a level of a priori truths and one of factual ones, what the world must necessarily be and what it actually is” (ibid.: 221). Put in a nutshell (ibid.: 394): “[E]very truth of fact is a truth of reason, and vice versa” So much for Kant's continued adherence to a dualism of form and content, or of the analytic and the empirical.
In order to explain himself, Merleau-Ponty (1962: 394) appeals to a phenomenological notion of “founding” (Fundierung), by which he has in mind a dynamic two-way relationship, in which one sort of truth serves to found another, which in turn acts back on the first sort, making itself more than derivative and the founding truth less than primary. That is to say, in our practical engagement of the world, we manage, especially by means of language, to transform truths of fact into truths of reason. Although the latter truths can never break entirely free from their founding facts, they become sedimented into cultural forms (into, as Wittgenstein would say,