Questions For Empiricists: by Vincent Cheung

Since sensation is so important to your view, I would like to understand what you are talking about.

What is a sensation? How did you learn the meaning of a sensation? How do you know when you are having a sensation? Do you sense the sensation to know that you have a sensation? If you sense a sensation, then how do you know that? Do you sense the sensation that senses the sensation? Then, do you sense the sensation that senses the sensation that senses the sensation? If this is not your view, then please explain. That is, if information comes from sensation, then how do you know when you are having a sensation?

Do you ever not have a sensation? How do you know that? Is a lack of sensation itself a sensation? Then, do you sense that you are not having a sensation? Can you have a sensation and not be conscious of it? How do you know that? Have you ever sensed that you are not conscious of a particular sensation? If so, then are you not in fact conscious of it? Does this not return us to the original question, that is, can you have a sensation and not be conscious of it?

Or, are you conscious of all the sensations that you are having? How do you know that? Do you sense that you are sensing all? But then, do you sense that you sense that you are sensing all? How do you know? By sensation again? Do you always sense everything around you? If not, how do you know that you are not sensing everything around you if you are not sensing everything in order to know what there is to sense and to know what is there but not being sensed?

How about radio waves? Are there radio waves? If so, do you sense radio waves? If you use a radio device to pick up these waves, then what are you sensing? The sound from the radio, or the radio waves? Do you hear words and music from the radio? If so, then are radio waves words and music? You might say that these are the “effects” of the radio waves. But then, you are only sensing the effects and not the cause. If so, how do you know the cause? If you infer from the effects to the cause, then how do you know that the inference is valid? By sensation again? What do you sense that would confirm this? Also, how do you know that you do not know certain things? By sensation? Again, is the lack of sensation a sensation? How do you know this? Do you sense that a lack of sensation is a sensation?

Then, if you know that you do not know certain things, what are these “certain things”? If you know what they are, then you must know what they are by sensation, but then, this means that you have sensed them – if so, in what sense do you not know them? Do you believe that the earth is flat, or that it is a sphere? If you believe that it is a sphere, then how do you know this? By sensation? How? Have you seen the earth from space?

Or do you trust the experts and the scientists? But then you did not sense what you claim to know, but you sensed only the testimony of these “experts.” Maybe you have seen a picture of the earth? But a picture is not the earth, so at best you sensed a picture. How do you know that the picture was not “doctored”? By sensation? How do you sense “not doctored”? Also, a picture is flat, so how is the earth a sphere?

The sun looks pretty flat to me. Now suppose that I look at the sun from space and see that it is spherical, then what am I suppose to believe? If we assert that the sun and the earth are spheres and that they rotate, then the rotation is not really sensed, but calculated. Even then, how do you confirm that no errors in calculation were made? Again by sensation? What do you sense to know this?

Also, do you believe in atoms? Have you sensed an atom? Even if you have, how do you know that there are atoms other than the one that you have sensed? Or are we just supposed to trust the scientists? Are they your pope? If you do not believe all that they say, then why do you accept some of what they say and not others when you have sensed neither (except for their testimonies, if even that)? Have they seen atoms? Have they seen the effects of atoms? If so, how do they know that those effects were produced by atoms? And still, maybe they sensed the effects (if even that), and not the atoms.

How did you learn your name? Did you accept a word as your name, just because people called you something enough times? I can think of a number of things to call you other than your name, but will you accept one or more of those words as your name or names if I call you those things often enough? Why or why not? If I call you “Ralph” twice, would you accept that as your new name? How about six hundred times? Why or why not? How often is “often enough”? How did you know that it was enough when you first accepted your name? Did you sense “enough”? Or the effects of “enough”? How? Are you Pavlov’s dog? But there is not always food after the sensation of the bell’s ring, is there? Or did you somehow make an inference from what you heard? If so, did you sense the inference? Please write out the process of inference in syllogistic form so you can exhibit its logical validity.

Do you like logic? Do you want to be rational? Then how did you learn the law of contradiction? If you learn all things by sensation, then how did you sense the law of contradiction? If you sensed it used or applied and then inferred this law, then is your knowledge still from sensation? Or is it from sensation plus logical inference? But then, how come you used logical inference before you learned the law of contradiction? Also, before you learned the law of contradiction, did you have sensations? If so, did you apply the law of contradiction to those sensations, so that a sensation could not mean one thing and its contradictory at the same time? If you did not apply the law, then how come all sensations were not nonsense? If you did apply the law, how could you do it before you learned it?

How did you learn the word “God”? If all knowledge comes from sensation, then have you sensed God? If you have sensed God, then why are you an atheist? If you have not sensed God, then maybe you heard the word and inferred the meaning of the word, but then by sensation you only learned the sound and not the meaning, since you inferred the meaning. But then, did you and I infer the same thing out of the sound? Do we mean the same thing when we say “God”? If we do not mean the same thing, then all the arguments you have against “God” do not apply to me.

As for the question of personal identity, how do you know that you are the same person today as you were yesterday? Do you sense that you are the same person? But cannot two different things give you the same sensation? If so, then the problem remains. If not, then how do you know? That is, how or what have you sensed that no two things in this universe can give you the same sensation, so that you can always distinguish between different things?