The Limits of Science
3 December 2014
P. F. Strawson called his twentieth century exposition of Kant The Bounds of Sense. I have commented elsewhere what a appropriate title this is. The Kantian project (much like metamathematics in the twentieth century) was a limitative project. Kant himself wrote (in the Preface to the 2nd edition of the Critique of Pure Reason): “…my intention then was, to limit knowledge, in order to make room for faith.” Here is the entire passage from which the quote is taken, though in a different translation:
“This discussion as to the positive advantage of critical principles of pure reason can be similarly developed in regard to the concept of God and of the simple nature of our soul; but for the sake of brevity such further discussion may be omitted. [From what has already been said, it is evident that] even the assumption — as made on behalf of the necessary practical employment of my reason — of God, freedom, and immortality is not permissible unless at the same time speculative reason be deprived of its pretensions to transcendent insight. For in order to arrive at such insight it must make use of principles which, in fact, extend only to objects of possible experience, and which, if also applied to what cannot be an object of experience, always really change this into an appearance, thus rendering all practical extension of pure reason impossible. I have therefore found it necessary to deny knowledge, in order to make room for faith.”
Immanuel Kant, Critique of Pure Reason, Preface to the Second Edition
What lies beyond the bounds of sense? For Kant, faith. And Kant’s theological agenda drove him to seek the bounds of sense so that speculative reason could be deprived of its pretensions to transcendental insight. Thus Kant gives us an epistemology openly freighted with theological and moral concerns. Talk about the theory-ladenness of perception! It is, however, non-perception — i.e., that which cannot be the object of possible experience — that is the Kantian domain of faith.
Of course, this is the whole Kantian project in a nutshell, is it not? It is Kant’s design to show us exactly how perception is laden with theory, the theory native to the mind, the a priori concepts by which we organize experience. Kant propounds the transcendental aesthetic and the transcendental deduction of the categories in order to demonstrate the reliance of even the most ordinary experience upon the mind’s a priori faculties.
Kant was, in part, reacting against the empiricism of Locke and Hume — especially Hume’s skeptical conclusions, although Kant’s own rejection of metaphysics equaled if not surpassed Hume’s anti-metaphysical stance, as famously described in the following passage from Hume:
“When we run over libraries, persuaded of these principles, what havoc must we make? If we take in our hand any volume; of divinity or school metaphysics, for instance; let us ask, Does it contain any abstract reasoning concerning quantity or number? No. Does it contain any experimental reasoning concerning matter of fact and existence? No. Commit it then to the flames: for it can contain nothing but sophistry and illusion.”
David Hume, An Enquiry Concerning Human Understanding, “Of the academical or sceptical Philosophy,” Part III
For Hume, the bounds of sense and the limitation of reason entailed doubt; for Kant the bounds of sense and the limitation of reason entailed belief. There is a lesson in here somewhere, and the lesson is this: from a single state of affairs, multiple interpretations can be shown to follow.
Are the bounds of sense also the bounds of science? It would seem so. In so far as science must appeal to empirical evidence, and empirical evidence comes to us by way of the senses, the limits of the senses impose limits on science. Of course, this is a bit too simplistic to be quite true. There are so many qualifications that need to be made to such an assertion that it is difficult to say where to start.
It should be familiar to everyone that we have come to extensively use instruments to augment our senses. Big Science today sometimes spends years, if not decades, building its enormous machines, without which contemporary science could not be possible. So the limits of the senses are not absolute, and they are subject to manipulation. Also, we sometimes do science without our senses or instruments, when we pursue science by way of thought experiments.
While thought experiments alone, unsupplemented by actual experiments, are probably insufficient to constitute a science, thought experiments have become a necessary requisite to science much as instrumentation has become a necessary requisite to science. Sometimes, when our technology catches up with our ideas, we can transform our thought experiments into actual experiments, so that there is an historical relationship between science properly understood and the penumbra of science represented by thought experiments. And thought experiments too have their controlled conditions, and these are the conditions that Kant attempted to lay down in the transcendental aesthetic.
There is also the question of whether or not mathematics is a science, or one among the sciences. And whether or not we set aside mathematics as something different from the other sciences, we know that the development of unquestionably empirical sciences like physics are deeply mathematicized, so that the mathematical content of empirical theories may act like an abstract instrument, parallel to the material instruments of big science, that extends the possibilities of the senses. Another way to think about mathematics is as an enormous thought experiment that under-girds the rest of science — the one crucial thought experiment, an experimentum crucis, without which the rest of science cannot function. In this sense, thought experiments are indispensable to mathematicized science — as indispensable as mathematics.
At a more radical level of critique, it would be difficult to give a fine-grained account of empirical evidence that did not shade over, at the far edges of the concept, into other kinds of knowledge not strictly empirical. Empirical evidence may shade over into the kind of intuitive evidence that is the basis of mathematics, or the kind of epistemological context that is the setting for our thought experiments. Empirical evidence can also shade over into interoception that cannot be publicly verified (therefore failing a basic test of science) or precisely reproduced by repetition, and which interoception itself in turn shades over into intuitions in which thought and feeling are not clearly distinct.
Where does Kant’s possible experience fit within the continuum of the senses? What is the scope of possible experience? Can we make a clear distinction between extending the senses (and thus human experience) by abstract or concrete instruments and imposing a theory upon experience through these extensions? Does possible experience include all possible past experience? Does past experience include phenomenon that occurred but which were not observed (the famous tree falling in a forest that no one hears)? Does it include all possible future experience, or only those future experiences that will eventually be actualized, and not those that already remain merely shadowy possibilities? Does possible experience include those counterfactuals that feature in the “many worlds” interpretation of quantum theory? Explicit answers to these questions are less important that the lines of inquiry that the questions prompt us to pursue.
. . . . .
. . . . .
. . . . .
. . . . .