Last time, I illustrated the difference between realism and instrumentalism, one species of anti-realism in the philosophy of science. I received no responses. Moving on, then.
Explanations vs. Excuses
These days we hear a lot of wondering about: “Should X have done Y? Was Z justified? Why W?” It is thus not surprising that the other day I encountered someone asking for the difference between explanations and excuses. I would like to bring that question to this presumably broader audience. In order to do that I would like to propose an answer and then presumably get reactions.
An excuse, as far as I can tell, is an attempt to mitigate or exonerate an action (or perhaps also a state) that has moral or ethical valence. By contrast, an explanation is, to put it in semantic mode, simply an answer to a “Why?” question. In that sense, one can provide an explanation as an excuse. For example, “Why did Johnny curse repeatedly, ‘Bastard! Bastard! Bastard!’?”
“He has Tourette syndrome.”
But not all explanations are excuses. This seems clear enough. For example, “Why did the pressure of this gas double?”
“The piston reduced its volume by half.”
Both of these examples illustrate some important features of explanations. One is that explanatory power comes in degrees. Neither explanation seems very explanatory. Why is this? They do not appear to appeal to a mechanism; they are merely subsumptive explanations — our singular event or state falls under generalizations. (Note: This itself seems to be a subsumptive explanation!)
What, then, is the alternative? The first guess at this is that not only does one need a generalization, but also some proposed mechanism. Not being a neurologist or a psychologist I cannot provide you with a mechanism to improve the explanation of the tics of someone with Tourette. However, if one uses the kinetic theory of gasses rather than the ideal gas law (as I did implicitly above), one can calculate that the particles of the gas will collide twice as often with the container walls if it is halved in volume and hence the pressure has increased twice.
This illustrates a few more characteristics about explanations. One is that sometimes they are bottom-up — the mechanisms appealed to involve the parts of the system. Another is the idea that explanations sometimes at least involve a boundary condition in addition to a generalization. This is important: Quantitative differences in the parameters of an oscillator, say, can have qualitatively different behaviours.
Third, the mechanism is only relative in character: I did not explain why the walls of the container and the particles of the gas are regarded as rigid, for example. This illustrates the fact that most proposed mechanisms involve one or more idealizations. In order to obtain more detailed and hence explanatory views of the world, one has to try to capture only a simplified view of it in thought and then complicate it, rather than try to grasp everything about it at once. This approach, while somewhat present earlier, I attribute primarily to Galileo, who is arguably the first one to realize it enough to defend it explicitly in his work.
I thus finish the column with some questions to help think through more aspects of explanation. I will leave questions about excuses for the next time, once we understand where the distinction may lie.
1. I remember borrowing my father’s electronic calculator when I was maybe about 10 and playing with the buttons. I understood +, -, and a few other symbols. But the radical sign (√) was unfamiliar. I tried to figure out what it did; numbers between 0 and 1 produced larger numbers; numbers greater than 1 were “made” smaller and numbers less than zero produced an error.
I asked my father “Why the error?” He told me that negative numbers did not have a square root, and told me what a square root was. I then asked: “Why do negative numbers not have square roots?” He did then tell me about imaginary numbers and “corrected” his earlier lesson. Are my “why” questions here requests for explanations? Are the answers my father gave explanations? Do they appeal to mechanisms in the way that I discussed? If they did, what are they? If they did not, why not, and could my father have given one?
2. The explanation I alluded to of the increased pressure in the gas sample appealed to a mechanism involving the parts of the gas (and its ambient conditions). Is this always so? Can you think of a “top-down” explanation that nevertheless appeals to a mechanism?
3. I said above that events or states can be the target of explanation. Is that always so? Consider: Body B moves at 10 meters per second west of the origin of coordinates for 10 seconds. Therefore B is now 100 meters away to the west. Is this an explanation? Hint: Is inertial motion an event? Is this a case of inertial motion?
4. Dan Dennett several times discusses examples surrounding a chess computer program, saying of it, “It likes to get its queen out early.” What would explain this fact about the program? Does it matter if the chess program is the single purpose of a standalone computer? Does the explanation have to be similar to that offered of a human player with the same sort of style of play? Does your answer change if a mechanistic explanation is wanted?
5. Roger Penrose thought that humans can solve computationally unsolvable problems due to quantum effects in microtubules of neurons. Discuss this case in the light of our discussion of explanation.
6. Michael Faraday in the 19th century was able to show that many purported demonstrations of the supposed truth of spiritualism were done by suggestion and excessive pattern seeking on the part of the participants. What explanations are involved here?