The book follows the mantra: Separate speculation from what you know and anchor on what you know. Chapter 4 explicitly does this, identifying what we know from accounting for the present and near-term future, but avoiding building speculation about the long-term future into a valuation.
There are parallels in scientific endeavor.
Think of cosmology. Scientists are interested in the course of our universe in the future, indeed many universes, and can speculate about that…the existential question, maybe. But what they look at is what is happening now and how it is changing. That guides forecasting of future changes. And so, conducting fundamental analysis of firms provides indications of what they might look like in the future.
Think of forecasting the effect of climate change in the future. Observation of what is happening currently is a starting point. Or go back to the past when there was a significant increase in temperatures (50-55 million years ago) and examine the fossilized sea life in the ocean sediments. Scientists find that that changed the atomic composition (oxygen isotopes) of sea life: A basis for prediction of the future.