Introductionin philosophy the debate on science is to what extent we need to discover the truths. This debate on the extent of the truth that is required to be discovered is more important when it comes to theoretical scientific theories especially theoretical physics. this part of physics which is defined recently couldn’t be seen or experimented. Instead it’s more like mathematical aspect of physics which does work out to define many different things, such as the most recent one string theory. some Philosophical interpretation however, doubts the reason for existence of this kind of theories which are more mathematical than experimental. For instance, scientific realists argue that all facts deserve to be discovered however constructive empiricism argue that facts are important when they empirically adequate and whether they can predict observable phenomena correctly. constructive empiricism which was developed by bas van Fraassen is not the best choice for theoretical physics since he didn’t admire metaphysical phenomena.  So there seems to be a problem in definition of truth in between this two philosophical point of view which, one is based on realism and the other however opposes realism, logical empiricism and instrumentalism in at least one fundamental view. In this essay I want to argue that all facts need to be discovered and there’s no difference between them if they’re observable or unobservable, which means I argue for scientific realism against constructive empiricism in terms of recently discovered sciences specially string theory.One of the other places where these two ideas clash is for instance, if we have phenomena ‘A’ and this phenomena has two different explanation as called ‘B’ and ‘C’, scientific realism would argue that one of the explanations  is more true (if they seem the same we haven’t discovered the case which one will work and other won’t) therefore that is what we should use instead of the other one however constructive empiricist would argue that they are exactly the same and they have same use as long as they can predict correctly therefore they might prefer one over another if has simpler maths or other reasons but in their eye they are exactly the same. One of the cases which we can see the same things happening is in wave and particle characteristics of light where the maths can work in both ways and they both have valid observations to prove the phenomena and theory however it’s more efficient for people to use the wave characteristics of light as the maths that is used is far easier than in particle characteristics.Scientific realism and constructive empiricism with applied string theoryBoth ideas of scientific realism and constructive empiricism are trying to give the best interpretation for science and how to encounter new scientific theories. In my opinion science should be defined as the discovery of true reasons for all phenomena in universe, therefore the true aim of science is to describe universe completely.Scientific realismScientific realism is epistemically positive view toward the content of scientific knowledge which recommend belief in both observable and unobservable world produces best theory which shows the metaphysical aspect of the scientific realism. Moreover, there are two other aspect for this aspect. One is called semantic and the other is epistemological aspect. Also, it aims for theories which are demonstrated as truth or approximate truth about observable and/or unobservable world (in this case old theories are grouped as approximate truth because although they were not completely true, but they were partially true) and these theories are called as best scientific theories as in scientific realist view. In common words scientific realism is based on a realistic view on the way universe works and to explain all observable and unobservable phenomena.MetaphysicalRealism is having an argue on existence of the world being mind-independently which is in contrast with any theory which is based on idealism which according to it there is no external world rather than the world which human mind could think of. Idealism although is historically used but could rarely be seen in new theories. accepting that theories could be metaphysical is the most important property of scientific realism which opposes constructive empiricism.SemanticAccording to realism, scientific entity of the theory either observable or unobservable should have literally truth values whether true or false. This aspect is in contrast with instrumentalism which explains all unobservable as instrument to predict world.EpistemologicallyCommitted to the idea that theoretical claims form knowledge of the world which contrast sceptical which says even if theories could have metaphysical and semantic view but they’re not powerful enough to talk about that knowledge and in this case anti realists could argue against the fact that just observables are powerful enough to have definite theories about the knowledge.believing in realism doesn’t mean you have to follow all 3 viewpoints, you can be a realist and just admire 1 or 2 of these viewpoints.In a scientific realism view string theory could be explained completely. firstly it has all of scientific realism aspects which as a metaphysical we are having strings which are having quantum fluctuations in a 26 dimensional world also the nature of strings which are two dimensional and although they are infinitely thin but they have a length of meter long which is a mind independent world but also we can have a sign of string theory in really high energies which is far beyond the energy that could be produced by human right now but having that much energy is not mind independently which shows that this theory having both idealist and metaphysical aspects. In the other hand the whole theory is based on so called “theory of everything” which the whole idea is a theory that could describe the world which adequate the whole realism idea which is to describe the world and its phenomena.Scientific Realism in my opinion could help to improve science constantly as allow science to have unobservable phenomena which we can predict mathematically instead of experimentally for instance one of the most important theories which have been discovered by Einstein was general relativity as we it was predicted mathematically before it can be experimented. general relativity lead to a better theory than Newtonian gravity, since it could predict accurately specially about high speed objects and also it could solve the problem with inaccurate calculation for mercury shift.Constructive empiricismConstructive empiricism is a form of empiricism which means that the only way to gain knowledge is sensory experience and emphasis the role of sensory evidence in the formation of ideas. This idea was introduced by Bas Van Fraassen who was a Dutch American philosopher. in his opinion any it is impossible to acquire knowledge from unobservable phenomena. which means most of the theoretical physics discoveries that doesn’t have an experimental proof, cannot be categorized as science and they are not representing truth. The acceptanceAcceptance of a theory in Constructive empiricism involves only the belief that the theory empirically adequate. Which means the only way to accept a theory is to not have any sort of information beyond human mind and also theory must obey the semantic view which is discussed completely in scientific realism and although constructive empiricism is against scientific realism but still they both agree on the fact that a theory should agree with the semantic aspect.The semantic aspect claims1) The theory’s claims are genuine statements capable of truth or falsity.2) Any literal construal of a theory cannot change the logical relationships among the entities claimed by the theory.[1]Therefore, string theory doesn’t agree with constructive empiricism because it doesn’t empirically adequate because it’s a theory which is not yet have been tested or there’s no empirical evidence for it and the only way to have empirical evidence about it is to reach the required energy which is still for beyond from what we could reach. But in the other hand string theory actually agree with the semantic view because its claims are capable of truth or falsity.In the other hand Van Fraassen conclude that observable is when something can be observed unaided, van Fraassen have made this point since two can understand an aided observation differently. However, this just applies to the subject of theory and not the whole theory.To sum up, these two philosophical prospective argue on the true meaning of science. Scientific realism argue that everything needs to be discovered and the way we understand the theory does not matter as long as it can be proved in any way such as mathematically or experimentally. However, constructive empiricist would argue that the only theories that are defined as science are those that are observable, because the phenomena subjected to theory cannot be understand in two different ways.In my opinion, scientific realism is better since it can improve science significantly with having same viewpoint about both observable and unobservable phenomena. With accepting unobservable phenomena as science, there is a chance of using the theories which predict them to improve our life. For instance, the idea of quantum computing which is based on an unobservable phenomenon however this idea is improving constantly until we can use it in future. However, within constructive empiricist view, this improvement in unobservable science and also applying it to a practical object cannot be done because the basic of quantum mechanics theory is not acceptable.Arguments for each philosophical viewthe whole problem and debate between constructive empiricism and scientific realism can be summarized into “defining science” and “science’s aim”. however, there are many arguments for and against each one which are listed below.No miracle argumentThis argument which is the most powerful motivation for realism claims the only explanation that renders the success of science to not be “a miracle” which means they need to have true description or approximately true description of the world, Therefore there wouldn’t be any explanation in science which will discuss a phenomena as a so called miracle and every theory will aim to describe the world completely which would not be the case for constructive empiricism, where any phenomena which isn’t mind independently should be called as miracle.Pessimistic inductionThis argument which is against both scientific realism and constructive empiricism, more generally towards science, and it worries that under determination and inference to the best explanation are generally conceptual in nature. Therefore, as in history there were many theories which regarded as successful but by the time passed it’s found out that they were wrong and believed to be false therefore pessimistic induction claim that this will happen in a point of time for current theories so therefore they are still false. this argument in my opinion couldn’t be solved because there will be always new phenomena to understand and therefore new theories which make the old theories wrong. So, unless with having an infinite knowledge of phenomena we couldn’t solve this argument in science.Inference to the Best ExplanationThis argument is for scientific realism against constructive empiricism. Inference to the Best Explanation holds that, out of potential explanations that we have for the same phenomena, we should conclude the best one is the true one. however, a constructive empiricist would conclude an unobservable explanation means that we’re claiming false for the explanation of our phenomena. this opinion is against the idea of “inference to the best explanation” which means constructive empiricism idea is against science in this case as one of science aims is to infer the Best Explanation. unlike constructive empiricism, scientific realism always argues for the best explanation whether it’s observable or unobservable.observable/ unobservable distinctionThis argument is against constructive empiricism and the idea of observable in constructive empiricism. In constructive empiricism, one of the significant problems is the clarity of difference between observable and unobservable. this argument can be divided into two parts.1)      Some phenomena are observable with instruments such as a microscope, in this case if we assume that these data are unobservable then we have significant part of the science being disallowed.  however, if we assume they’re observable then how are we sure about the data we’re getting since we’re not sure how accurate the instrument is as there is no possible way to measure it since we’re not able to observe the truth of what instrument is showing us.2)      Another argument is how to be sure what different people observe are exactly the same as there isn’t a possible way to know the way each person observes the world is the same as the other person.My argumentThis argument is for scientific realism and against constructive empiricism. The idea of scientific realism gives us more chance to discover more phenomena. By having more information that can predict the universe, it’s possible to use those prediction and understandings in terms of improvement. However, by just discovering observable phenomena, we wouldn’t have as much knowledge, which means there would be less improvement. Constructive empiricism also makes our knowledge more limited than it is.In my opinion scientific realism is a better interpretation for science. Firstly, because it allows both observable and unobservable phenomena and doesn’t refer to unobservable as miracle, which in my opinion is against the true meaning of science. Secondly, because it infers that the best interpretation is the true one and thirdly, it doesn’t limit the extent of science and with scientific interpretation it’s possible to define anything however by constructive empiricism we can just define what is observable.String theoryTo talk about string theory, we first need to have knowledge about general relativity and quantum mechanics.  General relativity was introduced by Einstein where heavy masses can distort space-time which is the reason for gravity and he proved it first mathematically in 1905 and then the experiments showed the same data in 1919 for light bending around large masses which strengthen the proof. By introducing general relativity, the whole idea of old Newtonian gravity was disproven where each mass can exert force on other mass relative to their masses and 1r2. In the other hand the theory of quantum mechanics was initiated with young slit experiment and improved by Heisenberg to produce the idea of uncertainty. However general relativity and quantum mechanics which are the basis of the modern physics cannot unite together to make a complete theory for physics as one has theorised the world of large masses and the other is about very small scales. So, there was a need of a theory to match up these two theories. In this case theoretical physicists came up with an idea which could be found in both real life and quantum ideas which is a string, they came up with an idea which was to assume the very fundamental form in a material is a string which can end up making both quantum mechanics and relativity to work but the biggest issue is that was, for the maths to work we needed 26 dimensions.Primary goal of string theory was to describe the strong interaction which was due to nuclear strong force but with improvements in quantum chromodynamics it’s been left as an idea. Until 1980’s which it started to be used for uniting gravity and also to describe many of the problems in supergravity theory. In this theory it’s been told that the most fundamental form in a material its strings not a particle. These strings are 10–35meter long which is Planck length and the tension in these strings are in order of Planck force which is 1044newton and infinitely thin and end of them are connected to branes.Branes are physical objects which generalize notion of point particles to higher dimensions. By rules of quantum mechanics branes can propagate through space-time. Branes just have spatial dimensions also they can have mass and charge.The strings in string theory have quantum fluctuations. These fluctuations which cause vibrational modes are the reason for different properties of particles.There are two different theories which are more common than others in string theory1) Bosonic string: the minimum amount of vibration allowed by quantum uncertainty is called “zero-point energy”. Every new dimension allows more quantum fluctuations which allow another direction to explore for the string.so more directions mean more zero-point fluctuations. In bosonic string by balancing vibrations and irreducible zero-point quantum fluctuations turns out there are 26 dimensions is the number which cancel out with the amount of vibration therefore leads us to massless string2) Superstring theory: superstring theory tries to explain the existence and movement of all the particles and fundamental forces of nature in one theory, by modelling them as vibrations of tiny supersymmetry strings. Unlike bosonic theory superstring theory accounts for both fermions and bosons, incorporating” supersymmetry” to model gravity. The most important thing about this theory is the fact that it cuts 26 dimensions to 10, therefore bringing new vibrational modes which allow strings to act like electrons (be their fundamental form). Superstring theory is more practical and realistic as it cuts out dimensions to just give ten dimensions required which one is temporal and nine of them are spatial.As we can see there are many problems with string theory one is the problem with supersymmetry of string theory. For the mathematics of string theory to work, physicists have to assume a symmetry in nature called supersymmetry, which creates a correspondence between different types of particles. One problem with this is that instead of the 18 fundamental particles in the Standard Model, supersymmetry requires at least 36 fundamental particles.Also, string theory failed to describe the accelerated expansion of universe which has been seen by astronomers. All these drawbacks and also the fact that string theory goal has been differed from what has been defined at the beginning caused theoretical physicists to rethink about the theory. I think although string theory might not be the actual truth, but it can lead us to the truth, as we have seen in the discovery of atom and the way it is where we started with theories which were completely wrong and getting closer and closer to the truth of structure of atom. String theory is a complete unobservable phenomenon in terms of constructive empiricism, because of order of magnitude it theorised about and also the number of dimensions. Therefore, this shows that string theory is not acceptable by constructive empiricism. However, this is different for scientific realism since the theory fits with scientific realism interpretation.  This shows that with having constructive empiricist interpretation it’s possible to miss many important theories which describe the universe therefore the idea of constructive empiricism in my opinion is against scienceConclusionThe argues which was introduced above shows that scientific realism is a better interpretation of science than constructive empiricism. Also, by applying scientific realism on string theory it’s possible to see that scientific realism does allow this theory to be a part of science. In my opinion having theories such as string theory, apart from being true or false, can improve science because having such theories can raise more questions about universe. For instance, in this case we have the question of do we have more than 3 spatial dimension and time? Which is raised due to its mathematical proof which needs 26 dimensions. These questions always cause the science to improve more rapidly. As it’s possible to see in history that having a false theory wasn’t bad at all for instance the idea of determination of inside of a molecule and then inside of an atom which although the first few theories were wrong but by improving the old theories we reach better theories. Another problem with constructive empiricism is the no miracle argument which was stated above. I think calling anything unobservable phenomena a miracle which is just true and happens is against the nature of science, which in my opinion the definition of science is, discovery of true reasons for all phenomena in universe and the aim of science should be to describe the universe. However, this aim would not be possible with constructive empiricism however we could get closer to this aim by using a realist interpretation.Bibliography1)      Monton, B. & Mohler, C., 2017. Constructive Empiricism. Stanford Encyclopaedia of Philosophy. Available at: https://plato.stanford.edu/entries/constructive-empiricism/ [Accessed December 23, 2018].2)      Van Fraassen, B. (2004). The scientific image. Oxford: Oxford University Press.3)      Chakravartty, A., 2017. Scientific Realism. Stanford Encyclopaedia of Philosophy. Available at: https://plato.stanford.edu/entries/scientific-realism/[Accessed December 25, 2018].4)      Greene, B. (2000). Superstrings, hidden dimensions, and the quest for the ultimate theory. Vintage.5)      5)Chalmers, A.F., 2011. What is this thing called science?, Buckingham: Open University Press.6)      Gubser, S.S., 2010. The little book of string theory, Princeton: Princeton University Press.7)      C., V.F.B., 1995. The scientific image, Oxford: Clarendon Press.8)      Bird, A. (2010). Philosophy of science. London: Routledge.9)      Hacking, J. (1983). Representing and intervening. Cambridge: Cambridge University Press.10)  Lipton, P. (2007). Inference to the best explanation. London: Routledge.11)  Feynman, R. (1981). Simulating Physics with Computers. [PDF] California: Department of Physics, California Institute of Technology. Available at: https://people.eecs.berkeley.edu/~christos/classics/Feynman.pdf [Accessed 2 Feb. 2019].