In the second half of the 20th century, two programmes of the unification of have confronted each other. One of them represents an up-to-date version of positivist thought according to which unification ought to be realized as the universalization of the method of mathematized natural sciences. The other programme sets out from Husserl's Krisis and it advocates the thesis according to which the emergence of modern natural sciences is an historical achievement; consequently their world-constitution is reversible; the task of unification should be undertaken by a universal philosophy. I have to state at the very beginning: my sympathy lies with the critical partner (the Husserlian school), nevertheless I do not share its programme. It is this disagreement that I want to corroborate in the following arguments.