Indirect Realism: A Plausible Theory Of Perception?

Indirect Realism: A Plausible Theory Of Perception? In this essay I am going to be examining some of the main claims made by indirect realism as well as looking at some of the fundamental problems these claims cause for the theory, such as the epistemological problem, the ontological problem, and the fact that the theory inevitably leads to solipsism. Indirect realism first arose in an attempt to resolve some of the problems faced by common sense realism, where it became apparent that the assumption that our senses almost always give us true information about the nature of the external world is implausible. Indirect realism therefore modifies the ideas presented by common sense realism, by suggesting that what we perceive directly and are immediately aware of is not the world or the objects within it, but sense data. Indirect realists are far from denying the existence of the physical world, but simply claim that the physical objects in the world cause our sense data, and that the sense data we experience represents the external world, to an extent. For example, when I see a horse, I do not perceive it directly, as common sense realism would suggest. I have no sensory contact with the horse, and what I am aware of is only a mental representation, sort of like an inner picture, of the horse. My visual experience is not directly of the horse; however indirect realism claims that it is caused by the horse. What I am aware of is the representation of the horse, which my senses produce. As Dancy explains, Indirect Realism argues that in perception people are indirectly aware of the physical worldà ¢Ã¢â€š ¬Ã‚ ¦in virtue of a direct awareness of internal, non physical objects.  [1]  This means that although someones idea of an object may resemble the object itself, a person can only ever be aware of their idea and never the object itself. Indirect realism also seems to provide a response to the objections to common sense realism, raised but the Illusion Argument. In the instance of colour, for example, one jacket can look completely different colours when viewed in different lights. If we were to then examine the fibres of the jacket material in more detail, we would probably find them to be a variety of different colours. The way it is perceived also depends on the viewer, for example, someone who is colour-blind may see the jacket differently to someone with full colour vision. In view of this, it doesnt seem to make sense to say that the jacket is really yellow, or that its yellowness is independent of the perceiver. In an attempt to explain this kind of phenomenon, indirect realism introduces the notion of primary and secondary qualities. Primary properties resemble the real properties of the object. John Locke, describes them as being utterly inseparable from the body  [2]  and necessary for conception of it. Primary qualities exist both in the world and in sense experiences, and can be experienced by more than one sense. They are measured by physics and are qualities which the object actually has, regardless of the conditions in which it is being perceived or whether it is being perceived at all. Primary qualities include shape, size, position solidity, extension, motion and rest, and number. Locke argues that secondary qualities are nothing in the objects themselves but powers to produce various sensations in us,  [3]  and conceptually inessential. These qualities exist only in sense experiences and can only be experienced by one sense, but objects in the physical world have the power to produce these experiences in us. It may seem as though these properties are really in the objects we perceive, for example, that the yellowness is somehow part of the yellow jacket, however the yellowness that we experience is simply the objects power to produce yellow images in a normal viewer, under normal conditions. The ideas we have of secondary qualities dont resemble the actual objects but are simply a product of the kind of sensory system that we have. Secondary properties include colour, temperature, smell, taste and sound. One major objection to indirect realism is that it seems to make the real world unknowable. It only makes sense for us to say that A resembles B, if it is possible for us to be directly aware of both A and B, in order for us to compare the two. This creates a rather fundamental epistemological problem for indirect realism because the theory states that our sense experiences of the primary qualities of objects resemble the actual qualities of objects in the external world, however, it also states that we can never be directly aware of the external world, so we therefore have no way of checking whether our sense experiences do in fact resemble the external world at all. For example, if my sense experience of a ball is round, I have no way to check that this corresponds with the actual shape of the ball in the external world. We are entirely limited to the evidence of our senses, and since these work by means of mental representations, it seems as though we can never gain any direct inf ormation about the actual properties of the ball, or any other object in the external world. Indirect realism has also led to a problem related to what is known as the veil of perception, which refers to things that are seen indirectly, and not as they are in themselves. This is because there is a veil that we cannot penetrate, because the things that are being perceived (in this case, objects in the external world) exist independent of sensation. This creates a rather fundamental ontological problem for indirect realism, because it only seems to make sense to say that A is caused by B if it is possible for us to know what B is, however the veil of perception seems to prevent us from doing this. Since we are unable to directly access any physical objects in the external world, it is possible that our sense experience could be caused by something entirely different, for example, Descartes evil demon, God, a mad scientist, the matrix, or ourselves. We have no way of getting outside of our own perception to find out what is causing our sense experiences, if there is in fact anything causing them at all. This is another serious problem for indirect realism; it can lead to solipsism, which is the belief that nothing exists beyond oneself and ones immediate experiences. It suggests that since we cannot know the external world and other minds directly, they may well not exist at all. Solipsism is argued to be philosophically absurd for two reasons; the first being the phenomenological reason, which claims that if we were the only beings that existed, we would not feel emotions such as shame, embarrassment and guilt, which require the existence of another person or being in order to have any effect. The second reason is that logically, solipsism just doesnt seem to make sense, and therefore any theory that leads to or allows for this view point, the way indirect realism does, is also argued to be absurd. In conclusion, it seems that although indirect realism does manage to overcome many of the problems faced by common sense realism, it also seems to create many more serious problems of its own. Although the theory at first seems quite plausible, the fact that it allows for solipsism makes it pretty much irredeemable. Indirect realism also fails to account for the causal relation between the external world and our sense experiences, and as we have seen through the veil of perception objection, we have no real reason to believe that our sense experience bare any resemblance to the external world at all. I think indirect realism would be much more plausible if it could offer some form of explanation of the interaction between our sense experiences and the external world. Mn0.5Zn0.5Fe2O4 Nano-material: Hydrothermal Synthesis Mn0.5Zn0.5Fe2O4 Nano-material: Hydrothermal Synthesis Title: Hydrothermal synthesis and photocatalytic application of Mn0.5Zn0.5Fe2O4 nano-material for degradation of Reactive Blue H5R dye In the proposed research work Mn0.5Zn0.5Fe2O4 nano material will be synthesized using hydrothermal technique for the degradation of reactive blue H5R dye. The chlorides of manganese, iron and zinc will be used for the synthesis of the Mn0.5Zn0.5Fe2O4 nano material. Then synthesized material will be used in water treatment for the degradation of reactive blue H5R dye through photocatalysis using visible light. The examination of the size of the particles and structural properties of the synthesized material will be carried out by using X-ray diffraction (XRD) technique and the morphology of material will be evaluated by scanning electron microscopy (SEM). Particle or grain size of prepared samples of Mn0.5Zn0.5Fe2O4 nano material will be computed using the Scherer’s formula. The photo-catalytic behavior of Mn0.5Zn0.5Fe2O4 nano material will be investigated by measuring the photo degradation rate of the dye. The stability of the nano-photo catalytic material will also be investi gated by the repeated use of Mn0.5Zn0.5Fe2O4. INTRODUCTION Synthetic dyes and different chemicals used in textile industries play significant role in environmental pollution. Some of these industrial chemicals and synthetic dyes decompose aerobically and anaerobically resulting in the formation of carcinogenic compounds (Neill et al., 1999). In the past few decades, there has been huge attention between scientists in increasing semiconductor photo-catalysts with great prospective for environmental protection applications like water disinfection (Ullah et al., 2012; Shahid et al., 2013). Most of the ferrite materials are known to show exciting photocatalytic capabilities for hydrogen or oxygen generation from water upon irradiation with visible light. Such visible light absorption properties, and their proper band edge positions with respect to redox levels essential for water splitting, are desirable for a water splitting photocatalyst to work under sunlight (Dom et al., 2014). Ferrite materials technology has now extended to a very progressive stage, in which the properties to a large extent are designed and controlled by engineers, to garb the particular function of the device. Because of their outstanding magneto-transport properties the mixed valence ferrites have involved huge scientific attention in the recent years (Ahmed and Bishay 2005). In the beginning works the ferrites were attained by soft chemistry and mechano-synthesis (Millotet al., 2007). Hydrothermal strategy is a promising synthetic method because of the low process temperature and very easy to manage the particle size. The hydrothermal procedure has several benefits over other growth methods such as the use of simple devices, catalyst-free growth, low cost, large area uniform production, environmental friendliness and less harmful (Aneesh et al., 2007). Moreover, no post-heat behavior is needed for the created nanoparticles, which makes this method extremely suitable as heat treatment might result in particle collection. (Haw et al., 2002) OBJECTIVE The objective of present research work is to produce Mn0.5Zn0.5Fe2O4 nano-sized particles by hydrothermal technique specifically for catalysis of reactive blue H5R dye. The structural properties of synthesized nano-photocatalyst will be studied by using X-ray diffraction (XRD) and scanning electron microscopy (SEM). Photo-catalytic behavior of the Mn0.5Zn0.5Fe2O4 nanoparticles will be investigated by determining the photo degradation rate of the reactive blue H5R dye under visible light irradiation. Review of Literature Rath et al. (1999) synthesized Mn0.65Zn0.35Fe2O4 particles in nanosize (9–12nm) using metal chlorides via hydrothermal precipitation. The characterization was done with TEM, XRD, and VSM. The concentration of chloride ion and pH of precipitate played a vital role in retaining the preliminary stoichiometry of the solution of the nano-material. Whereas at low pH, incomplete precipitation of Mn was observed. Zn loss in the nano-particles at higher pH of precipitation was noted. Bujoreanu et al. (2000) investigated the structure of manganese ferrite in powder form which was prepared by co-precipitation method using MnO2 and FeSO4.7H2O. The powder material then was co-precipitated and aged at temperatures ranging from 55 to 59 oC, then washed and dried in the air at room temperature. By the addition 15% sodium hydroxide solution in the 2N cation solution the stoichiometric amounts of MnO2, FeSO4.7H2O and H2SO4 were precipitated Kosak et al. (2004) prepared nanocrystalline MnZn-ferrite with different morphology through single water-in-oil micro-emulsion comprising of n-hexanol, surfactant CTAB and an mixed metal sulfates solution. The mixture was precipitate with sodium hydroxide solution and oxidized with hydrogen peroxide. The prepared nano materials were characterized by using X-ray diffraction (XRD), BET surface analyzer, magnetometry and transmission electron microscope (TEM). Abdollahi et al. (2004) synthesized various compositions of manganese Mn doped ZnO. using precipitation method. XRD, TEM, SEM, EDX, BET techniques were used for characterization. The band gap measurement was done with UV-visible reflectance. XRD pattern showed no impurity peaks, indicating Mn-related secondary phases. The EDX showed the slightly lower amount of Mn doped on ZnO than the theoretical value and SEM showed that 1% Mn-doped ZnO well ordered morphology, homogeneous distribution of slightly lower particle size and low aggregation. Vaidyanathan et al. (2004) compared Mn0.9Zn0.1Fe2O4 synhesized through double sintering method and chemical co precipitation method in order to find the magnetic properties. The precipitated ferrites showed altered magnetic properties like magnetization (Ms), coercive field (Hc) and Curie temperature (Tc). The particles were reduced in size as compared to co-precipitated nano-sized particles. Arulmurugan et al. (2006) prepared by Mn1−xZnxFe2O4 used for ferro-fluid preparation.TG-DTA, XRD, TEM, VSM and Mossbauer spectroscopy was used for description. The ultimate approximated cation contents decided with the initial degree of substitution. The particle size and curie temperature (Tc) reduced with the rise in zinc substitution. The particles with greater zinc concentration, showed ferrimagnetic and super paramagnetic behavior at room temperature. Yimin et al. (2007) synthesized Mn1-xZnxFe2O4 using metal sulfate in aqueous ammonia. The TEM, XRPD, VSM and TGA were appled to demonstrate the material properties. The classification of the nanoparticles was evaluated and discussed. The effects of the reacting components and preparation methods on the Curie temperature, the magnetization and the size distribution of Mn Zn ferrite nanoparticles. Hejase et al. (2012) produced hyperthermia inducing agents manganese zinc iron magnetic nanoparticles. The structure was recongnized using scanning electron microscopy, X-ray diffraction, and a superconducting quantum interference device. The curie temperature, saturation magnetization, remnant magnetization, coercive field, and hysteresis were analyzed which showed that adapting the Mn contributed to the modification of properties of the magnetic complex. Shahid et al. (2013) synthesized high effective ZrFe2O5 nanoparticles using co-precipitation method. By (EDX) the chemical composition of nano-materials were analyzed. (FE-SEM) was used to study the morphology. The structural properties of the produced material were appraised by XRD technique. By evaluating the degradation rate of TBO dye in aqueous solution the photo-catalytic action of ZrFe2O5nano-particles was examined under visible light irradiation in the presence of ZrFe2O5nano-particles. By increasing time of exposure under visible light irradiation a steady decrease in absorption peak was noticed. As after 140 min of contact to visible light the 92% degradation effectiveness was detected. Besides, ZrFe2O5nano-photocatalyst could be recaptured and reprocessed purely. The rate of TOC elimination and TBO was decreased by only 10% and 5% respectively, afterward seven cycles of use, representing the more photo-stability of the synthesized nano-photo-catalyst material.