Status Updates From Sete breves lições de Física

We are born and die as the stars are born and die, both individually and collectively. This is our reality. Life is precious to us because it is ephemeral.

That which makes us specifically human does not signify our separation from nature; it is part of that self-same nature. It’s a form that nature has taken here on our planet … Who knows how many and which other extraordinary complexities exist, in forms perhaps impossible for us to imagine, in the endless spaces of the cosmos?

Our moral values, our emotions, our loves are no less real for being part of nature, for being shared with the animal world, or for being determined by the evolution that our species has undergone over millions of years. Rather, they are more valuable as a result of this: they are real.

The “I” who decides is that same “I” that is formed (in a way that is still certainly not completely clear, but that we have begun to glimpse) from reflections upon itself, through self-representations in the world, from understanding itself as a variable point of view placed in the context of the world, from that impressive structure that processes information and constructs representations that is our brain

We have a hundred billion neurons in our brains, as many as there are stars in a galaxy, with an even more astronomical number of links and potential combinations through which they can interact. We are not conscious of all of this. “We” are the process formed by this entire intricacy, not just by the little of it of which we are conscious.

When we say that we are free, and it’s true that we can be, this means that how we behave is determined by what happens within us, within the brain, and not by external factors. To be free doesn’t mean that our behavior is not determined by the laws of nature. It means that it is determined by the laws of nature acting in our brains.

These conditions, nevertheless, are not, as Kant imagined, universal—deducing from this (with obvious error) that the nature of Euclidian space and even of Newtonian mechanics must therefore be true a priori. They are a posteriori to the mental evolution of our species and are in continuous evolution. We not only learn, but we also learn to gradually change our conceptual framework and to adapt it to what we learn

The images that we construct of the universe live within us, in the space of our thoughts. Between these images—between what we can reconstruct and understand with our limited means—and the reality of which we are part, there exist countless filters: our ignorance, the limitations of our senses and of our intelligence. The very same conditions that our nature as subjects … imposes upon experience.

For a hypothetically super sensible being, there would be no “flowing” of time: the universe would be a single block of past, present, and future. But due to the limitations of our consciousness we perceive only a blurred vision of the world and live in time. Borrowing words from my Italian editor, “what’s non-apparent is much vaster than what’s apparent.”

where does it come from, our vivid experience of the passage of time? I think that the answer lies in the intimate connection between time and heat. There is a detectable difference between the past and the future only when there is the flow of heat.

“As vivid as it may appear to us, our experience of the passage of time does not need to reflect a fundamental aspect of reality.”

special relativity has shown that the notion of the “present” is also subjective. Physicists and philosophers have come to the conclusion that the idea of a present that is common to the whole universe is an illusion and that the universal “flow” of time is a generalization that doesn’t work.

It is not impossible for a hot body to become hotter through contact with a colder one: it is just extremely improbable.

it is statistically more probable that a quickly moving atom of the hot substance collides with a cold one and leaves it a little of its energy, rather than vice versa. Energy is conserved in the collisions but tends to get distributed in more or less equal parts when there are many collisions. In this way the temperature of objects in contact with each other tends to equalize.

“The difference between past and future exists only when there is heat. The fundamental phenomenon that distinguishes the future from the past is the fact that heat passes from things that are hotter to things that are colder.”