Sunday, February 1, 2015

How do we discover that something doesn't exist?

Hilary Putnam once asked a funny question:  If all of the things we have heretofore called cats turned out to be robots from Mars, would we have discovered that all cats are robots or, rather, that there are no cats? Putnam went with cats are robots, and on the basis of this intuition he argued that the extension of a term- the set of objects to which it refers- is not determined by our concept of it, but rather by its paradigm cases.

This view is now known as semantic externalism, and I'm largely down with it. Though I actually think it's a mistake to discuss things like this as if we were discovering the real meaning of meaning. The truth about meanings is that they are conventional and we can change them anytime we agree to. If scientists decided in such a case that there were no cats, and invented a new term to refer to these robot thingies instead, no grievous error would have occurred that philosophers would be required to go back and set straight. I see Putnam not so much as having discovered part of the real meaning of meaning, but rather as having made a strong, useful proposal for rationalizing some of the conventions by which we allow meanings to change.

Putnam's robot cat example can seem pretty out there to someone not acquainted with the crazy thought experiments philosophers use in an effort to clean up our conceptual framework. But the history of science and philosophy is replete with similar episodes in which we need to determine whether some phenomenon doesn't exist, or, rather, is just very different than we had supposed, i.e., veditwhasup.*

Here is a slightly different take on robot cats- which I believe is compatible with Putnam's views- in terms of the concept of explanation. What I'll suggest is that whether we decide that a phenomenon doesn't exist or is just veditwhasup depends a great deal on the explanatory context.

Start with witches. Although a large chunk of  humanity still believes in witches, in a scientifically enlightened community it is uncontroversial to say that there are none. How did we get from a position of near universal belief in witches, to the view that witches don't exist? I say the reason we say there are no witches is that the phenomena to be explained have disappeared. There was a time when we were in dire need of an explanation of how people get turned into newts. The widely accepted explanation is that it was due to witchcraft. Since then, we have come to doubt that humans do get turned into newts. Hence, we are no longer in need of witches to explain this.

Last year I discussed a few important scientific episodes in which the phenomenon to be explained was determined to be an illusion.  Some of these cases we may understand in a manner that is analogous to the above. For example, we do not say that planetary epicycles are veditwhasup.  We say that they don't occur, because retrograde, the phenomenon they were invoked to explain, is an illusion. We do not say that the designer of plants and animals is just veditwhasup, because we have come to realize that design itself is an illusion. For the same reason we no longer require the gods as an explanation of fate. If you ask why some things are fated to happen, regardless of what we do to prevent them, you are laboring under an illusion.

However, this particular explanatory model does not fit all the cases, even in the realm of superstition. For example, epilepsy was once widely explained by reference to demonic possession. But we did not reject possession on the grounds that epileptic fits are illusions.  Similarly, in science we did not reject the existence of caloric and phlogiston because heating, cooling and combustion do not occur. We no longer believe in humors nor miasmas, but that is not because there is no such thing as the diseases they explained. We reject the élan vital and the soul, but that is not because we no longer believe in the unity of consciousness or the self-organizing properties of living systems.

In these, and many other cases, the reason we have stopped believing in these entities is that we have hit upon radically different and better explanation of the phenomenon in question. When this occurs, it often makes sense to reject the existence of the entities we are appealing to in explaining the phenomenon, but not the ones we are trying to explain.

What's interesting is that this is very often exactly what people do recommend.

For example, philosophers and scientists often claim that if determinism is true there is no such thing as free will. But if free will is just the remarkable human ability for deliberative choice, of course it exists. All we have rejected is a ghost in the machine explanation of it. A similar point holds for the concept of knowledge. People often conclude that there is no such thing as knowledge when they learn that certainty is unachievable or that the notion of our ideas resembling an external reality makes no sense. But all this means is that we had a false explanation of how knowledge works. Veditwhasup. Again, people often claim that there is no such thing as human altruism when they learn that people get pleasure from helping others.  But this is foolish. Human cooperation and self-sacrifice happens. We just had a very wrong idea of how.

In sum, there are two good reasons for thinking that some theoretical entity or process we previously accepted does not exist. The first is that it explains as real what we have come to regard as an illusion. The second is that we have developed better and fundamentally different explanations of the reality in question.  Failing either of these, I would suggest raising the following question. Could it just be veditwhasup?

Randy Mayes
Department of Philosophy
Sacramento State University

*Either of Old Saxon origin or coined by me just now as an acronym for the purpose of staying under the 1,000 word limit imposed by this blog.


  1. You provide historical cases supporting your claim that there are two very different ways in which we have changed our mind and came to believe that some theoretical entity (or process) we previously accepted does not exist.

    I believe you’ve made a solid argument. However, you might consider generalizing your position by focusing on knowledge acquisition. When some belief becomes an obstacle to knowledge acquisition, then it is properly rejected. This obstacle could be a belief in the existence of some theoretical entity or process, but it also could be an entire worldview.

    Consider this poem:

    FLOWER in the crannied wall,
    I pluck you out of the crannies,
    I hold you here, root and all, in my hand,
    Little flower—but if I could understand
    What you are, root and all, and all in all,
    I should know what God and man is.
    -- Alfred Lord Tennyson

    Tennyson is poetically espousing a Hegelian worldview that essentially involves the Doctrine of Internal Relations. In defense of this doctrine, the 19th century English philosopher F.H. Bradley said, “Develop what is implied in what is before you, and you will find yourself committed, on the principle of the flower in the crannied an all-comprehensive system in which everything is bound by necessity to everything else.” Hegel and Bradley would have said the flower in the wall is essentially connected to the acceleration of balls falling off the Leaning Tower of Pisa and to who will be the next president of the United States.

    This Doctrine of Internal Relations is rejected by Galileo, who had a very different worldview. He believed that for the purposes of fruitful knowledge acquisition one should control variables and do piecemeal empirical inquiry into a specific kind of phenomenon, say falling balls, without paying attention to their accidental relationships to crannied walls and the next president of the U.S.

    In opposition to Galileo, both Hegel and Bradley promoted the idea that to gain true knowledge a person should first try to explain everything by finding the secrets of nature before worrying about falling balls. But Newton came down on the side of Galileo. Bertrand Russell realized that it was Newton and Galileo, not Hegel and Bradley, who had a better understanding of knowledge acquisition, and so Russell became a strong opponent of the Doctrine of Internal Relations. He eventually influenced most all Anglo-American philosophers to reject the doctrine and adopt a worldview that promotes metaphysical realism, empiricism, and scientific analysis.

  2. Brad, this is interesting, thanks. Of course, I'm focusing narrowly here on the question when we should express ourselves as rejecting the existence of a previously accepted entity or process as opposed to having discovered that it is veditwhasup. So I take it that your suggestion here would be that we should outright reject when remaining committed inhibits knowledge acquisition. I suppose I agree with that, but I'm inclined to think that this is the sort of determination that we make only with a lot of historical perspective. If, for example, you imagine someone like Einstein claiming that we should reject belief in the ether altogether because it is inhibiting knowledge acquisition, the appropriate response would be to ask him how he knows something like that. And it seems to me that the convincing reason is that he has a much better explanation of the the results of the Michelson Morley experiments that does not require the ether. Or, without the advantage of hindsight, imagine Lee Smolin arguing simply that string theory is inhibiting the growth of our knowledge in fundamental physics. Again I think he is answerable to the question how he knows that, and I suspect that something like the explanatory analysis I propose is what people would be looking for. So I guess without having said it I am trying to characterize this issue more in terms of criteria that could figure usefully into a local debate. Though I take your point that intuitions like those expressed by Hegel/Bradley and Galileo/Newton do figure into the outcome.

  3. Randy, Very lucid argument. I have a trivial criticism and a larger doubt. The trivial criticism is that many of the phenomena that witchcraft supposedly explained are still with us: e.g. people getting sick and dying, having strings of bad luck, having accidents, not finding a partner, losing things, etc..
    The larger doubt concerns the way you subsume recent philosophical debates under the pattern you describe. I’m not sure if the fit is quite right in some cases.
    E.g. altruism. The phenomenon to be explained here is presumably that people act altruistically sometimes. It seems as if what you’re saying is that the “explanation” of this used to be that people acted in a purely selfless way, with no admixture of pleasure or self-interest. We no longer think this. So we still think altruism is real, but we explain it differently. But I don’t see positing pure selflessness as an explanation of altruism in the first place. I’d say what we’ve done here is modify our notion of altruism in a sensible way.
    E.g. free will. The phenomenon to be “explained” is presumably our feeling that we make choices, that we could have done otherwise, and that we are ultimately responsible for our choices. I see that the “ghost in the machine” explanation is now rejected by many. But what’s the “radically different and better” explanation of the phenomenon in question? My impression is that the debate still rages: some say the feeling in question is illusory, some say it’s not.

  4. Em, thanks for the perceptive comments.

    I agree with you about witchcraft. What you say shows that it fails at the second explanatory level as well We've come up with better and radically different explanations of those phenomena.

    Re: altruism. I'm not entirely sure I follow you. It seems to me that many people think of acting with, say, a perfectly good and pure will, as consisting in the ability to act solely for the benefit of others without any benefit or anticipated benefit for ourselves. So a person's capacity to do that is what we would invoke to explain actions that seem to fit this description. I would rather say it is a poor explanation, since it is uninformed by any plausible psychological mechanism, than that it is not an explanation at all.

    Re: free will. I would say that the phenomenon to be explained was, in the beginning, the alleged fact that we make free choices (in the precise sense you describe), not that we feel that we do. I would say that we have simply misdescribed the facts. The facts of free will are that we often deliberate and choose a course of action, and that we do this in a way that allows us to both plan and avoid danger at qualitatively different level than all other beings we know about. I think the battle that rages on is the explanatory project of figuring out exactly how the brain does that.