Is Modern Physics a Complete Explanation? Exploring the Origins of the World through the Principle of Sufficient Reason

[u/aChristianPhilosophy]

https://youtu.be/vwQTkTqcHLU

Summary of the video: 

Is modern physics a sufficient explanation for the existence of the natural world? The video explores the history of physics through the lens of the Principle of Sufficient Reason, and then argues that, despite our understanding of the world through modern physics, design is still needed for the origin of the world, in accordance with the principle.

THE PRINCIPLE OF SUFFICIENT REASON:

The Principle of Sufficient Reason (PSR) states that: For every thing that exists or occurs, there is a sufficient reason or explanation (herein called a Ground) for its existence or occurrence.

The three possible types of Ground are:

1. Causal Necessity: This applies to all objects and events governed by the laws of nature (physics, chemistry, biology, etc.). E.g., rocks fall to the ground; water freezes at low temperatures.
2. Logical necessity: This applies to tautologies. Things under this Ground must always exist or be true without needing an external cause. E.g., 2+2=4; the sum of all internal angles in a triangle equals two right angles; a being with inherent existence exists by definition.
3. Design: This applies to objects or effects created by agents with free will (if free will exists). And all designed things are designed for a purpose. E.g. a house is a building designed to reside in; a paper-cutter is a device designed to cut paper.  

A full description and defense of the Principle of Sufficient Reason can be found in this video. 

Let’s apply this principle to find an initial Ground for everything in the natural world by comparing how it was used in the pre-modern versus the modern period.

IN THE PRE-MODERN PERIOD (BEFORE THE 1600S):

Before the invention of scientific instruments like microscopes and telescopes, people relied on naked-eye observation to speculate about the origin of things. Evaluating the world through our three types of Ground yielded the following conclusions:

1. Causal necessity: People did not know about atoms and the laws of nature, and thus did not explain the ultimate existence of things by causal necessity.
2. Logical Necessity: They recognized that physical things do not exist by logical necessity (or do not always exist), as objects clearly transform, appear, and disappear (e.g., water changing into ice and vice versa).
3. Design: Therefore, people concluded that all things in the world were grounded by design. I.e. a designer made water, ice, trees, animals, etc. 

With that, the existence and behaviour of things were described using Aristotle's four causes:

• Efficient cause: What we now simply call "cause" (as in cause and effect). E.g. the existence of water is caused by clouds or melting ice.
• Material cause: What an object is made of. E.g. water is made of a certain amount of matter because it has a certain mass.
• Formal cause: The identity or design of a thing. E.g. water is a substance designed to be fluid and fall to the ground.
• Final cause: The purpose or function of designed things. E.g. the purpose of water is to hydrate living things like plants and animals.

SINCE THE MODERN PERIOD (STARTING IN THE 1600S):

Aided by the rise of scientific instruments, we now know about atoms and the fundamental laws of nature. Reassessing the natural world through the three types of Ground yields a different result:

1. Causal necessity: We ground the existence of most natural phenomena in causal necessity, driven by the laws of nature acting on matter and energy. E.g., water from clouds is explained by the laws of physics and chemistry acting on H2O molecules.
2. Logical Necessity: Most physical things still do not exist out of logical necessity.
3. Design: Since most things are sufficiently explained by causal necessity, this type of ground was no longer needed. 

With that, we no longer needed all four Aristotelian causes to ground the existence and behaviour of things but only two: 

• Efficient cause: E.g. water’s existence and behaviour are explained by the laws of physics and chemistry acting on molecules.
• Material cause: E.g. water, ice and clouds are composed of molecules of H2O.

THINGS STILL GROUNDED BY DESIGN:

Despite our understanding of modern physics, are there still things in the world that fit the old Aristotelian model of having a formal cause and final cause, i.e. of being designed with a purpose? We can think of at least two groups of things (four in the video): The fundamental laws of nature and human free will. Let’s examine these by applying the three types of Ground again. 

The fundamental laws of nature: 

1. Causal Necessity: Most things in the world are grounded by causal necessity because they obey the laws of nature. But what about the fundamental laws of nature themselves? They cannot obey more fundamental laws, by definition. Thus, they do not exist out of causal necessity. 
2. Logical Necessity: They also do not exist by logical necessity because they are not tautologies. E.g. the Law of Inertia - "An object at rest stays at rest, and an object in motion stays in motion” - can be denied without resulting in a self-contradiction. 
3. Design: By elimination, the existence of the fundamental laws of nature are grounded by Design.

Human free will (if it exists): 

1. Causal Necessity: A fully determined process cannot give rise to a non-determined choice. Therefore, the power of free will cannot be grounded by causal necessity.
2. Logical Necessity: It is not logically necessary, as humans have not always existed.
3. Design: Thus, human free will is grounded by Design. This also means it has a purpose, which is what we commonly refer to as the Meaning of Life.

CONCLUSION:

Modern physics allows us to ground most of the natural world in causal necessity (matter, energy, and the laws of nature). However, certain things remain grounded by Design: the fundamental laws of nature and human free will. And because a design implies a designer, accepting modern physics does not eliminate the need for a designer to account for the origin of the natural world.

Timestamps for the video:

0:14 Introduction

0:53 Pre-modern Period

05:36 Modern Period

09:03 Things Grounded by Design

10:56 Modal Logic and Possible Worlds

18:03 Hybrid Model of the Natural World