In the Jehovah's Witnesses book on Creation/Evolution, we find the paragraph:
On the other hand, there is ample evidence to support the conclusion that the spontaneous generation of life from nonliving matter is not possible. "One has only to contemplate the magnitude of this task," Professor Wald of Harvard University acknowledges, "to concede that the spontaneous generation of a living organism is impossible." But what does this proponent of evolution actually believe? He answers: "Yet here we are - as a result, I believe, of spontaneous generation." Does that sound like objective science?1954 is a long time ago, particularly in an area of science that is advancing rapidly. However, I dug up the article, and discovered that Wald's very next sentence was:Life: How did it get here?, 1985, page 51
Reference to: Scientific American August 1954, page 46
It will help to digress for a moment to ask what one means by "impossible."Wald then spends more than a page on how the colloquial meaning of "impossible" is different from the scientific meaning. He argues that the colloquial meaning is the wrong one to use, because the problems are too far removed from what a non-scientist is used to.
So, the quoted sentences were strictly rhetorical. Wald was creating a problem, so that he could launch into his answer. The article as a whole is indeed objective science. The reason the quote sounds odd is because it was quoted out of context.