Hospers challenges the view of a radical sceptic of that there is no knowledge for everything is doubtful by providing vital grounds on how it can ultimately be attained and by adopting the two different senses of knowing, the strong and weak sense. He then fortifies his argument by proving the incoherence of a doubter. This essay will look on his arguments against radical scepticism and finally to what extent it is successful. In his argument, he emphasises on the three main requirements for knowing, one is that the thing has to be true, secondly, one has to believe in that thing and lastly it requires that one has adequate evidence to believe that the thing is true. Firstly, the truth requirement is necessary for if it is not, would be self-contradictory since knowledge cannot come from something false. Secondly, it requires that one has to believe that the thing is true for believing is an eminent part of knowing. Nevertheless, for a thing being true does not require that it is believed to be true. For instance, it is true that there is another dimension aside the world we are living in though some may not believe. So what if it is true and it is believed to be true?
Would such true belief suffice the term ‘knowledge’? A sceptic may reply that even we have believed a thing to be true; we were not in the position to know it, for it is merely just a lucky guess. The last requirement, the most vital of all is that we must have evidence to believe that a thing is true. Notwithstanding, the adequacy of evidence remains an unsolved puzzle. How and when can evidence ever be countable? Surely one cannot extract the whole evidence; hence would leave a probability of false belief. In arguing the reliability of the senses, Hospers came up with the two types of senses. The weak sense of knowing applies regularly in a general manner. It involves things which we know in common. For example, tomorrow the sun will rise. We say this in the weak sense given that, there is a room for doubt for the evidence we hold to support this claim is inconclusive. In contrast, a strong sense of knowing requires that we have absolutely conclusive grounds for the belief of a thing being true.
Furthermore, in his criticism, he uses a reversal approach, this time experimenting the doubter’s position. The doubter does not believe in the thing and believes that the evidence for the thing to be true is inadequate. However, if the evidence is insufficient, then could he specify further tests to finally resolve his doubt? If not, thus conclusively, his doubt becomes incoherent, for the word ‘doubt’ has become an empty formula. Thus by this point, a radical sceptic’s position is put under threat. Nevertheless, one might argue that although Hospers’ argument, particularly in attacking the doubter’s position is seemingly successful but is rather flawed.
His argument focuses mainly on the criteria of knowing, that is of how and when knowledge can be wholly attained but little does his argument do in shaking the stance of a radical sceptic. It seems that we can only know things in the weak sense and not in the strong sense. Thus it means that not all evidence can be extracted, in turn leaving room for doubts. Therefore, a radical sceptic’s position might still be prevailing at some point. To conclude, Hospers argument against scepticism proves useful particularly in understanding the concept of knowledge but as to whether it has utterly solved the issue of doubts remains a sceptical point as a sceptic would point out.