Some like Stephen Hawking are still looking forward to the discovery of the GUT despite all the failures of the past. Together with this optimism came a way of doing research through foundational thinking. All knowledge can be deducted from axiomatic knowledge in an objective way. The first problems with this approach began to show up in the beginning of the 20th century when scientists could not agree on what the foundation from which everything else should be deduced is. It became increasingly clear that there is no such foundation.
Axiomatic knowledge is more a matter of intuition than objectivity.
The discoveries in the middle of the 20th century dealt some other severe blows to Modernism. First Einstein's Theory of Relativity showed an interaction and a dependency between matter and energy that questioned long held assumptions about the world. Then Heisenberg's Uncertainty Principle showed a limit on our knowledge about the smallest particles. Smallest particles behave in an unpredictable way and can only be talked about in terms of probability. Most scientists seem to think of natural law nowaways in terms of approximations of reality if not just models in our brains to be able to predict probable future behavior.