4.5 OBJECTS OF EXPLANATION
We have seen in the first section of this chapter how navigating through a world populated by things ready-to-hand requires a pre-conceptual understanding which discloses in advance the structure of the world as a totality of involvements and guides man’s employment of those things for the sake of his own possibilities. We have argued in Section 3 that, by contrast, navigating through the contemplated world populated by present-at-hand things requires a conceptual understanding which explains how and why they are connected to each other and then showed in Section 4 how that explanation unfolded at various moments in human history. However, as we pointed out above, the modern scientific project, banished both God and Man from its territory and skipped over the inner nature of things themselves when it set up the Cartesian object. That project can therefore no longer answer the question ‘why’; all it can do, is ascertain through measurement how objects behave, not why they do so. One may want to argue at this point that objects behave the way they do because they must obey natural laws which we discover when we ascertain that behavior. But surely, calling the cause of that behavior a law is hardly an illuminating semantic change. In what way is then the modern scientific project to handle the ‘why’ component of the explanation which man nevertheless still feels compelled to provide to himself?
For an answer to this question, let us return to the quotation from Heidegger which we have given before in this chapter:
With this thing, for instance, which is ready-to-hand, and which we accordingly call a hammer, there is an involvement in hammering; with hammering, there is an involvement in making something fast; with making something fast, there is an involvement in protection against bad weather; and this protection ‘is’ for the sake of providing shelter for man—that is to say, for the sake of a possibility of man’s Being.
Here, man pursues the goal of providing shelter for himself by involving things with each other in a purposeful combination—things such as the hammer, the nails, and the material to be fastened into a shelter. This combination of things outlines a mechanism for getting his goal accomplished. If man were God, he could simply have willed the goals he was pursuing into being by fiat; such as it is, however, he must set about constructing a mechanism for using things by means of which those goals could be attained. Correspondingly, the scientific project—whose job after all is to provide the conceptual replacement for the pre-conceptual understanding which guided the construction of that mechanism—has no choice but to attain the explanatory ‘why’ it seeks through an explanatory ‘how’, not the explanation of how objects participating in our scientific experience behave, but rather the description of the mechanism by means of which one such object influences the behavior of another; the ‘why’ explanation thus unfolds in terms of a ‘how’ explanation which illuminates the 'means by which' one object becomes responsible for the behavior of another. This switch from a ‘why’ to a ‘how’ explicitly taken as a ‘by what means’ is not an arbitrary step; it is rather a natural consequence of the fact that man, finite creature that he is, must forever pursue his goals by manipulating things, in other words, by setting up mechanisms through which things can be made to conspire with each other to help him attain those goals.
In the modern scientific project however, objects of experience cannot just simply get involved with each other to form a mechanism explaining the means by which they might influence one another because man, the agent who uses his pre-conceptual understanding of the structure of the world to envision the mechanisms by which he attains his goals, is also missing from the contemplated world which he is trying to explain. The scientific project therefore conceives of a new type of object playing the role of an ‘agent’ which gathers objects of experience together into a mechanism designed to explain the means by which they influence one another, an object we may preliminarily call an ‘object of explanation’ to distinguish it from the possibly different objects of experience which populate the contemplated world. Thus, for instance, earth attracts the moon 'by means of' a gravitational force which, whether an instantaneous action at a distance or a propagating field, is conceived as an object which earth ‘deploys’ to reach out to the moon, much like man would reach out for the hammer. Force, particularly gravitational force, is thus the object of explanation which Newton suggests would mediate mechanical influence between bodies.
The same situation which obtained for mechanical experience, also obtains for all other types of experience considered in the scientific project. We shall illustrate the point by considering experiences involving optical, thermal, and electrical phenomena, as well as phenomena that can be traced to the inside of things. First, let us consider optical experience. What is fundamental for us in optical experience was well stated by Ernst Mach in his 1913 Principles of Physical Optics:
Certain objects, such as the sun, a flame, or glowing iron, are observed to be visible in themselves, whilst others, such as a piece of chalk, wood, cold cooper, are visible only in the presence of the former. We call the first class of objects self-luminous, the second class, dark. An observer can have no doubt that the visibility of a dark object depends on the presence of a self-luminous one, that the object so illuminated can by reflection illuminate another one, and so on.
In accordance with the axiomatic comportment towards things that founds modern science, this description of the visibility of objects is a taking in advance of what visibility must be. Within the horizon opened by that taking, objects stand out as optically connected to each other, in that the visibility of one is influenced by the presence of another. The reason why one object influences another this way cannot however be provided by a project which has banished Apollo from its domain and must therefore be finessed by seeking instead a means by which that influence is effected. The scientific project therefore posits that luminous objects emit light, an object of explanation which we freely conceive in our mind and which propagates, either as particle or as wave, to other objects where it is responsible for making them visible to us. Mach goes on therefore to say:
We call the sum total of the physical relations between one object and another, determined by the feature of visibility of the first object, the condition of illumination. The mechanism imagined to be involved, conditioned by the first object, is designated briefly as light.
Second, consider how Maxwell characterizes thermal experience in terms of a thermal equilibrium between two bodies:
The distinction between hot objects and cold ones is a familiar experience to all, and is associated in our minds with the difference of the sensations which we experience in touching various substances, according as they are hot or cold. The intensity of the sensations which we experience in touching various substances is susceptible of degrees, so that we may estimate one body to be hotter or colder than another by the touch. The temperature of a body is a quantity which indicates how hot or how cold a body is. Simple measurements of temperature with a thermometer establish that if two bodies of the same temperature are brought in contact with each other the resulting temperature is the same with the original one but, that if one is at a higher temperature than the other, that which has the higher temperature becomes colder and that which has the lower temperature becomes hotter.
James Clerk Maxwell, Theory of Heat (1908)
Here, as in explaining mechanical experience, we rest our explanatory structure upon giving ourselves a cognition in advance: two bodies of the same temperature are in thermal equilibrium with each other, equilibrium which manifests itself in that their temperature remains unchanged upon contact. The scientific project decides in advance that what plainly appears to be a lack of any thermal activity between two objects of the same temperature is, in fact, a state of equilibrium maintained by thermal exchange. This position does explain how the two bodies might thermally influence each other but why, under the circumstances, they should do so is not something we can answer at all within the context of the scientific project. Rather, we replace the ‘why’ with a ‘how’ taken as a ‘by what means’ and conceive of an object of explanation called heat which serves as a mechanism through which the connection occurs:
We find the cooling of a hot body and the heating of a cold body happening simultaneously as part of the same phenomenon, and we describe this phenomenon as the passage of heat from the hot body to the cold one. Heat then is something which may be transferred from one body to another, so as to diminish the quantity of heat in the first and increase that in the second by the same amount. When heat is communicated to a body, the temperature of the body is increased. When heat leaves the body there is a fall of temperature.
James Clerk Maxwell, Theory of Heat
Third, consider electrical experience. How a rubber rod, which has been previously rubbed vigorously with a piece of flannel, and the gold leaves of an electroscope behave when they are brought in the vicinity of one another is well established by observation, as are the various other electrical phenomena that follow from there. The reason why they do so, however, cannot be given directly but must be provided as a proposed mechanism through which the rod influences the leaves. Specifically, we conceive of two electric fluids, one called positive and the other negative. They are somewhat like substances in that the amount of them can be enlarged or diminished, but the total in any isolated system is preserved. Two electric fluids of the same kind repel each other, while two of the opposite kind attract. These fluids are objects of explanation. The fact that the scientific project eventually replaced these substances with electrons is not relevant to our argument concerning the necessity of introducing them.
Finally, consider our experience with the constituents of matter. We focus our attention on the motion of small particles submerged in a liquid, the so called Brownian motion, because that phenomenon explores the inside of things in the most immediate fashion.
We have only to examine under the microscope a collection of small particles suspended in water to notice at once that each one of them, instead of sinking steadily, is quickened by an extremely lively and wholly haphazard movement. Each particle spins hither and thither, rises, sinks, rises again, without ever tending to come to rest.
Jean Perrin, Atoms
How the Brownian particles move has been exhaustively observed by Perrin himself and others; they found that the agitation of the particles does not originate either in the particles themselves, or in any cause external to the liquid, but must be attributed to something that happens inside the fluid. However, as we argued in Chapter 2, we do not have direct access to that inside. Therefore, the scientific project skips over the fluid of our experience and determines in advance that the inside of a fluid is constituted of molecules which are in a constant, haphazard mechanical movement. These molecules, which are objects conceived in our mind, collide with the Brownian particles and are thus responsible for their observed behavior. This mechanism, by which the fluid affects the Brownian particle, explains why those particles dance around incessantly when suspended in it. Like gravitational force, light, heat, and electric fluids, all constituents of matter are therefore also objects of explanation.