Vincent Cheung writes:
As my readers are aware, I deny that induction, sensation, and science can yield any knowledge, and I have provided biblical and rational justification for this denial in my writings. Besides the typical fallacious replies and evasions, one response is to ask, “But what is knowledge?” That is, if we cannot define knowledge, or cannot justify our definition of knowledge, then it would seem meaningless to say that induction, sensation, and science cannot yield any knowledge.
I have tolerated this sophistry for a while, but since I have been asked about it several times, and since I have been made aware that this point is sometimes brought up in discussions about my writings (as if it totally destroys my arguments!), I will briefly address it here.
It is true that when we use a word, we should often have a proper and justifiable definition for it. This is especially important when we are using it in the context of precise arguments and syllogisms. However, the above objection misses the point.
The point is that induction, sensation, and science involve fallacious reasonings such that they can never produce logically valid conclusions from the premises. That is, it is impossible to use induction, sensation, and science to validly reason from premises X and Y to conclusion Q regarding any subject P. Thus our main point stands even if we never define or even mention “knowledge.”
Assuming the premise, “I see a red car,” how is it possible to validly reason from this premise to, “There is a red car”? You need another premise to fill in the gap between “I see” and “There is,” but how is this premise to be rationally obtained and justified, rather than just stubbornly assumed? This is the point.
As it stands, there is no rational difference between jumping from “I see a red car” to “There is a red car,” and jumping from “I imagine a red car” or “I desire a red car” to “There is a red car.” What is the rational difference between sensation, imagination, and expectation? How come one can jump from “I see” to “There is,” and cannot jump from “I imagine” or “ I desire” to “There is”? What is the additional premise that makes the difference? And how is this premise rationally obtained and justified? The issue is not even the definition of knowledge, but the validity of the reasoning process.
The objection is sophistical and irrational. Whether or not we define knowledge, and whether or not our opponents define knowledge, the objection has not even started to justify induction, sensation, and science, but it seeks to distract us from the main point.
But if the challenge is to define “knowledge” in a proposition such as, “Science cannot yield any knowledge,” then let our opponents first define “science,” and then logically demonstrate how it can validly reach any conclusion about anything, and then we can proceed to examine our denial. For if our science-loving opponents have never claimed that science can reach rational conclusions about anything, or even yield “knowledge” (whatever that is), we would have never needed to make the denial in the first place.
In other words, I can affirm everything that I have said regarding induction, sensation, and science without ever using the word “knowledge” — I just have to say some things differently. In fact, I have already done this a number of times in my books. For example, I would say that science cannot validly deduce anything about reality. And even “reality” does not need to be defined to make this point, since anything X will do — “affirming the consequent” is fallacious regardless of what you are talking about.
So let’s get back to the real issue and press our opponents to show how induction, sensation, and science can validly reason from premises to conclusion.
To those who agree with me: We are right about this. Our position is biblical, rational, irrefutable, and so obviously so that it is laughably easy to defend. Just don’t let intellectual tricksters bully or distract you, and don’t let them smuggle in their irrational theories by falsely claiming biblical support, as if false assumptions can be founded on true presuppositions, or the lie justified by the truth. Instead, let us continue to crush the man-centered epistemologies of induction and sensation, and to exalt biblical revelation as the sole infallible source of true premises from which we would validly deduce conclusions about the many things that God has chosen to disclose to us.
Gordon Clark writes:
With great reluctance, for I sincerely admire the considerable talent of my present opponent [George Mavrodes], I must point out that he has not met the issue when he says, "Sense experience is required for the derivation of such [Biblical] beliefs," and "every consistent epistemology which assigns a role to the Bible…must assign a role of equal scope and in precisely the same area to sense perception." To make such assertions presupposes satisfactory answers to Aenesidemus and Descartes' demon. Can it be shown that an impostor twin is impossible? Can we be sure that we have not overlooked a "not" in the sentence? There are even greater empirical scandals than these. How can one prove the reliability of memory? Any test designed to show which memory is true and which is mistaken presupposes that a previous memory is true - and this is the point in question. In large measure the psychological force of my position derives from the impossibility of empiricism.
No one in the history of philosophy has made a more determined effort than Aristotle to build knowledge on sensation. Surely Locke is no better; and contemporary phenomenalism with its experience that is neither mental nor physical is as meaningless and unverifiable as Spinoza's substance that is both. It was for this reason that the first Wheaton lecture used Aristotle as the exponent of empiricism. Therefore until my destructive analysis of Aristotle (in the first Wheaton lecture and in Thales to Dewey) is overturned, an appeal to sensation is a petitio principii.
The statements of these creeds mean that adherence to Scripture is not a deduction from sensory experience, nor the result of anticipations of decency, nor even of archaeological confirmation. Confidence in Scripture is the result of the inward working of the Holy Ghost.
This too is how Abraham knew it was God and not Satan who commanded him to kill Isaac.
By way of reply:
i) There is a very place for the witness of the Spirit in Christian epistemology. But unless the Bible is an object of knowledge, the Spirit cannot witness to the Word of God. And Clark fails to explain how, if sense knowledge is denied, the Bible can be an object of knowledge.
ii) There is nothing wrong with raising philosophical objections to empiricism. There is nothing wrong with introducing thought-experiments like those of Descartes and Aenesidemus.
But is it not self-refuting to prove scripturalism by appeal to extra-Scriptural objections to empiricism?
Scripture itself never says that sensory perception is a systematically unreliable source of knowledge. So Clark and Cheung are imposing on Scripture an extra-Scriptural frame of reference.
iii) I’d add that Cheung’s objection to sensation and induction is overstated and ultimately self-refuting.
It’s easy to show that our senses can be deceived. Take the familiar case of optical illusions.
It’s easy to show that induction is incomplete. It’s easy to show that scientific measurement is approximate.
But the very act of showing the limitations of sense knowledge presupposes that its limitations can be shown, and they can only be shown on the same type of evidence, drawn from a broader database.
We know that an optical illusion is illusory because we can subject it to more stringent empirical analysis, or simply because, as a matter of experience--either direct or testimonial--we have learned that a mirage is just a mirage.
Likewise we know that induction is incomplete because we know or can show the sample or the control group in the first place, and compare it to a larger potential pool.
By the same token, we know that a measurement is approximate precisely because we have a number of observable measurements to work with. And they are approximate within a certain range of variation.
This is why engineers build a certain margin of error into their designs. And this is why, as a rule, bridges and skyscrapers and aircraft are safe to use. Has Clark never flown on an airplane or driven across a bridge?
In other words, it is only because the senses are generally reliable that we are in a position to detect optical illusions or degrees of imprecision. Without that sensory benchmark, Clark and Cheung would have no frame of reference to observe--and I do mean “observe”--the limitations of sense knowledge.
It is only by comparing one observation with another than an observer is aware of any discrepancy to begin with.
iv) True, this leaves us with the question of why we should privilege some observations over others.
Without attempting to offer a general answer, it is sufficient for our present purposes if we privilege those observations which the Word of God has warranted. That’s a starting-point.
v) Cheung, for one, is using sense data to make his case against sense data. There he is, at his keyboard, with its alphanumerical keys, typing linguistic tokens onto a screen and sending them into cyberspace, to be read of someone else’s screen, through the material medium of optical fiber technology.
vi) If Cheung denies the possibility of sense knowledge, then perhaps he can answer me this one question: what evidence is there than Vincent Cheung even exists? Perhaps he’s a figment of the Cartesian demon? Certainly I find him nowhere named in my concordance of Scripture.
And how can I be sure that I haven’t overlooked a “not” or two in his case for scripturalism?
How, indeed, can I be sure I haven’t overlooked a “not” in a sentence of Scripture? How can I be sure the Bible is not a figment of the Cartesian demon?
For that matter, a rationalist with a faulty memory is in exactly the same boat as an empiricist with a faulty memory.
All the arguments cut both ways. So Cheung needs to be very careful that he doesn’t bleed to death as he hacks away at sense knowledge--for he is wielding a double-bladed sword, and it has a nasty habit of rebounding on the swordsman.