In professional as well as in lay communities, science is too often taken in a very limited (and arguably conceited, as we shall see) sense that science is a theory about naive external and objective reality in Nature.1.4 In this view, Nature is passive and mechanistic. It is therefore very often argued that the meaning-giving human beings, equipped with all their consciousness, artistic creativity, free will, and moral judgment, ``naturally'' can not be a part of passive and mechanistic Nature. This leads many to believe that a new scientific account of meaning is impossible right from the start1.5. But this does not have to be the case. Let us see why.
To clear the matter up a bit, let us consider what ``scientific account'' means anyway. We have just encountered our first question of meaning. And I hope the following discussion will shed some light on what a scientific account of meaning would look like. Now, as far as ``an account of meaning'' (call it 
) is concerned, a scientist is a person who believes in and strives for intelligible accounts of meaning (an intelligible account is an explanation one finds persuasive and rational). Moreover, a scientist is a naturalist, at least when she practices her profession. A naturalist is a person who believes that in the realm of discussion there is no account other than those found in Nature1.6. Armed with these concepts, we can reformulate our target as
a naturalist intelligible account of meaning.
At this moment, an objection to the possibility of this account can be largely attributed to the belief that Nature is passive and mechanistic. For many, this position seems to be the only choice, for Nature seems to consist of matter and matter follows the Law of Nature without exception; but human beings seem to be able to ``break the law.''1.7 In this sense, one could say matter is passive and objective but mind is active and subjective. If this view is correct, a naturalist has to answer this question:
why are mind and matter so different in that mind is active and subjective but matter is not?
Convinced that the pre-condition of this question is correct (i.e. matter and mind are inherently different), an antagonist of the naturalist intelligible account of meaning has a point. This renders the question untouchable, because it does not need any further explanation (it can be taken as it is). Nevertheless, this question sounds quite similar to a question à la Newton: why are earthly bodies and heavenly bodies so different in that an apple falls but the moon floats? -- remember the properties of heavenly bodies were an untouchable scientific question in the Middle Ages. For Newton, it turns out that the question has a simple answer: the moon does fall, so does the apple, and indeed so does everything. Asserting that, the age-old Aristotelian tenet of differentiating celestial from terrestrial body falls apart! Would the answer to the question above be the same? -- that matter (indeed the physical world as a whole) is active too?! Or, alternatively, the mind is also passive and our subjective intuition is only delusion?! If it is the second case, we end up with another theory of zombies, and the reader should stop reading right away because nothing makes sense anymore. On the other hand, if it is the first case, we have to revise our conventional way of thinking of objectivity. This is a monistic view1.8 of the universe relying on the refutation of Cartesian dualism. At this point, it seems to me that a ``better'' naturalist intelligible account of meaning must be a genuine monist theory.
The monistic approach to mind and matter is not a new idea. In fact, it can perhaps be traced all the way back to Democritus' theory of atoms and his stance as a panpsychist. In the era of classical physics and rationality, however, monism has given way to Cartesian dualism [9] and lost its influence Although seldom explicitly taught, Cartesian dualism is still deeply embedded in the way classical physics is presented. It remains the case even as the crucial argument of René Descartes (1596-1650) -- the concept of God has deteriorated ever since. Ironically, an extreme form of materialism (disguised as a sort of monism, although it is not, as we shall see) has emerged from Cartesian dualism.
To see how deep-rooted Cartesian dualism is in the alleged monist materialism, let us consider the orbit of Pluto as an example. The orbit of Pluto is presented in the textbook as a movie-clip in the eye of an external observer -- in the ``God's view,'' so to speak, although Pluto's period of revolution is much longer than the life expectancy of today's human and it has not even completed a single revolution since its discovery. So from human's view, the observation (or the experiment) is not even finished yet. What we have is only a firm belief that Pluto will follow its course pretty much like Earth follows its course. (It is very likely the case, but it is a belief nevertheless, therefore qualitatively different from absolute objectivity.) In fact, it is only from the ``God's view'' -- and indeed, one needs very strong faith in it -- that a naive (viz. objective) materialism can emerge. Since objectivity must be established by an external observer, the observer can not be a part of the universe -- which, by definition of monism, must include everything. Now it is clear that the absolute observer is the subjectivity being smuggled in. Consequently this can not be a genuine monism. In fact, this is one of most important motivations for us to shift our interest from ontology to epistemology and see the whole matter from inside out. A consequence of this shift is the so-called positivism. But a naive positivistic view of Nature cannot work either.
Thanks to the standard textbooks of sciences, today many students of science hold a naive positivistic stance that the purpose of science is to ``model natural phenomena as closely as possible''. That is, to offer predictions of natural phenomena as accurately as possible. This seems to be an epistemic approach. But the naivety lies literally in this view, because it begs for a model and an objective standard of ``closeness.'' It is nevertheless dualism in disguise. The implicit dualist stance will become clearer if we pose the following two questions: who is modeling? and to what is the model considered close? For one thing, there must be the absolute objectivity (the matter in Nature) to which scientific theory (in the mind of scientists) can model and the numerical prediction can approach. For another, the concept of model itself tears up the universe into what is modeling and what is being modeled. In fact, this view of separability has been subject to question in modern physics and in a way has motivated the epistemic approach to science.
Let us begin with the fundamental question posed by quantum theory. Indeed, it can be argued that a sort of proto-mind must be embedded in the sub-atomic phenomena which are not separable from their physical properties (in a quite obscure and indirect way, however). For one thing, in quantum mechanics, the observer -- this is extended by a set of measurement instruments that obey classical mechanics -- may play a crucial role and influence the experiment outcomes dramatically. In certain experimental arrangements, for example, an electron will shy away from a particular property if it ``knows'' that it is being watched (see Section 3.2 for details). In these cases, the absolute objective view has to be modified, if not given up. In a sense, quantum objects have some mind-like properties which make a monistic approach to mind and matter attractive again. Observing this fact, the qualitative question above is not justified and should be transformed to a quantitative one:
in which situations should we talk about an object is matter-like and/or mind-like?
This will be a crucial question addressed in this thesis. And indeed, quantum mechanics offers a handy formalism not only for physical objects but also for mental ``objects.'' This will comprise the basis of our naturalist intelligible account of meaning.