Deductivism and the Informal Fallacies

I want to propose and defend a general thesis concerning the nature of all fallacies of reasoning. One and all of which I maintain in distinctive ways are deductively invalid. More importantly, I want to say that the most accurate, complete and charitable reconstructions of these species and specimens of the informal fallacies are instructive with respect to the individual character of each distinct informal fallacy. Reconstructions of the fallacies as deductive invalidities are possible in every case, if deductivism is true, which means that in every case they should be formalizable in an expressively comprehensive formal symbolic deductive logic. Naturally, the only thorough way to convince anyone of the truth of the thesis would be to provide reconstructions of all of the fallacies as deductive invalidities. Only then can someone judge whether deductivism offers a good analysis of what are called the informal fallacies as specific types of deductive invalidities. What I propose to do instead is to take a seldom-discussed fallacy of particular interest owing to Walter Burleigh in his c. 1323 work, De Puritate Artis Logicae Tractatus Longior (Longer Treatise on the Purity of Logic).