There are many papers in the arxiv that require some as yet to be found particle, for the said papers to be valid such as. the axion. http://en.wikipedia.org/wiki/Axion the Graviton. http://en.wikipedia.org/wiki/Graviton the Higgs boson http://en.wikipedia.org/wiki/Higgs_boson When i say valid i mean that, if the required particle is proven not to exist the paper is falsified. This leads me to ask, where will theories lead if the existence of any, all of these particles are found not to exist? But it is not just" missing particles", huge chunks of the mass of the universe are missing. Dark energy, http://en.wikipedia.org/wiki/Dark_energy Dark matter http://en.wikipedia.org/wiki/Dark_matter So i ask the same question. Although some theories do not require some of this missing "stuff", these theories seem to be on the fringe of main stream science, i am not sure how many if not all are falsifiable, but unless some of this missing ,"stuff" , is found then it seems nearly every paper on this subject is falsified.