Philosophy

It is the question of testability and the issues revolving around it develop a meeting point between string theory and intelligent design. As string theory asserts the mathematical possibility of a intelligent cause behind creation, the basic postulate of intelligent design as intelligent cause gets a logical support. Still, even if the existence of intelligent cause is logical, it is not enough to be the logic of the intelligent creator.

Logical Vs scientific
The scientific basis of both String Theory and Intelligent Design are often questioned from the ground that they are not testable. It embraces the basic scientific proposition that authentic claims must be verifiable against evidence. But, it could be argued well that intelligent design and sting theory could be tested in principle and by definition although there are no apparent ways to do so. If it is the case, it could be argued that its matter of the technological advancement of the humanity rather than the theoretical flows of string theory or intelligent design.

The idea that there can be an intelligent cause behind the creation of everything does not automatically endorse the existence of an intelligent designer. It means that the very idea of intelligent design itself could be a refutation of a creator. String theory too imagines the models of creation in which certain intelligent causes are inevitable. It is not impossible to mathematically endorse such a view point. The point is that the existence of intelligent cause is not something beyond the natural.

On the question of falsifiability, one could argue that the falsifiability hypothesis itself is not falsifiable.  Moreover, is it effectively possible to falsify Darwinism Here, the logic is that universal cannot be proved without the universal. Universal can take place through particular but particular cannot prove the universal as particular itself is constituted by the universal. Putting it differently, the universality of the universal cannot be proved but the particularity of the universal or the universality of the particular can be proved. If we can understand that the particularity of the particular is self-explanatory, we must also be able to understand the universality of the universal as self-explanatory.

Predictability is also a measure of scientific theorisation. Here, the obvious question is about theories that do not predict. The theoretical formulation of both intelligent design and string theory does not necessitate engagement in prediction. When the Anthropic Principle of String tells life exists, it means that the the universe has properties such that life can exist. Here, life or life particle need not be predicted and the impossibility of prediction of something that has already take place is certainly logical.
Moreover, string theory and intelligent design are theory of everything. It is the scale of the universe which is the explanatory subject for both the traditions. String theory and intelligent design not only try to bring under everything under its theorisation but also it extends the borders of knowledge or theory into the farthest. This farthest point is where natural and supernatural could possibly meet up. It has been argued that if correct string theory could revel God blueprint for creation. Of course, there can be a blueprint for the creation but it does not necessarily need to be of Gods.

Conclusion
The testability of string theory and intelligent design is not a question that can address the overlapping theme of both as they are inherently designed to capture the universal from the standpoint of the universal itself. What is logical, not the scientific governs the rules of  universal because it has no reference point outside.