I have read this book numerous times over the last ten years and I think it offers the only truly hopeful path for the current impasse that exists between philosophy/religion and the numerous popularizers of contemporary science. What Polanyi shows (himself a chemist turned philosopher) is the way that in reality scientific knowledge, like all knowledge, has an ineradicably personal element to it. That is, you learn to be a scientist not by studying test tubes but by being an apprentice to someone who already is a scientist, who teaches you, disciples you, so to speak, trains you in how to know things in a scientific way. The key element is personal trust, you must trust them, have faith in what they are teaching you, believe in them and the truth, the reality of what they're teaching. This trust aspect is the 'tacit dimension' to all scientific (and every kind of human)knowing. Not only is it interpersonal at the start, all of our knowledge also includes our involvement in a community of fellow knowers (not unlike a church!). They help to validate our knowledge, they correct us, they serve to adjudicate our discoveries. Polanyi's point is that this personal knowledge is the only kind of knowing there is, even though it is not the kind routinely set forth by scientists in their own accounts of what they're doing and what they know. The force of his description is to take away the false dichotomy between supposedly objective 'factual' knowledge and purportedly subjectively impure 'beliefs.' All knowing has a faith-based foundation to it and we're all on the same ground when it comes to arguing for coherent views of the world, of what is and what's not. It's a great book, far from easy, but as important as any book of the last century. Read it!