FOR SINCE THE CREATION OF THE WORLD HIS INVISIBLE ATTRIBUTES: ta gar aorata autou apo ktiseos kosmou: (John 1:18; Colossians 1:15; 1 Timothy 1:17; 6:16; Hebrews 11:27) (19; Deuteronomy 4:19; Job 31:26-28; Psalms 8:3; 33:6-9; 104:5,31; 119:90; 139:13; Psalms 148:8-12; Matthew 5:45)

For (1063)  (gar) is a subordinating conjunction which Introduces the explanation of how God made a knowledge of Him evident to all mankind.

Creation (2937) (ktisis) refers to bringing something into existence which has not existed before.

World (2889) (kosmos) describes an orderly arrangement and here refers to the order of the universe. The Greeks used kosmos to refer to the universe from the fact of its perfect arrangement. It was used in this case as opposed to the Greek word chaos which was used by the Greeks of the first state of existence, the rude, unformed mass out of which the universe was made. Thus the Greeks believed that the original state of the universe was one of chaos which is in line with the theory of evolution and the so-called "big bang" theory, which has been "exploded" by Creationists and believing scientists, even though this theory is still held to tenaciously by the majority of the scientific world.

Invisible (517) (aoratos from a = without + horáo = see) is that which cannot be seen with physical eyes.

Visible Nature speaks of nature's invisible God.

In (Psalm 19:1-6) David writes that...

1 The heavens are telling (LXX = set out in detail) of the glory of God;
   And their expanse is declaring (LXX = proclaiming openly) the work of His hands.
2 Day to day pours forth speech,
   And night to night reveals knowledge.
3 There is no speech, nor are there words;
   Their voice is not heard.
4 Their line has gone out through all the earth,
   And their utterances to the end of the world.
   In them He has placed a tent for the sun,
5 Which is as a bridegroom coming out of his chamber;
   It rejoices as a strong man to run his course.
6 Its rising is from one end of the heavens,
   And its circuit to the other end of them;
   And there is nothing hidden from its heat.

Note the repeated emphasis in Psalm 19 - "telling", "declaring", "pours forth speech", "reveals knowledge", "utterances". And the extent of this clear proclamation - "all the earth", "end of the world". Observe that in the opening verse of Psalm 19, David writes that "The heavens are telling (LXX translates the Hebrew word for "telling" with the verb anagello in the present tense  = the heavens are continuously announcing in detail) of the glory of God"

In short anyone who has ever looked into the glittering night sky or at a radiant red-orange sunset has no excuse to not believe in God!  But humanity today prefers Hollywood or computer video games to seeing the "things" of the glorious God in the heavens. Beloved, when was the last time you walked outside and gazed at the moon and stars made by our Creator?
 

Did you observe the paradox in Romans 1:20? invisible things which are visible! This state of things has been true since the creation of the universe. The eternal power and Godhead of the Creator have been since that time and are now understood by the things that have been made, namely, the material creation. Man, reasoning upon the basis of the law of cause and effect, which law requires an adequate cause for every effect, is forced to the conclusion that such a tremendous effect as the universe, demands a Being of eternal power and of divine attributes.

Charles Hodge wrote that God...

...has never left himself without a witness. His existence and perfections have ever been so manifested that His rational creatures are bound to acknowledge and worship Him as the true and only God” (Hodge, C: Commentary on the Epistle to the Romans Grand Rapids: Eerdmans)

ALL CREATION IS AN OUTSTRETCHED FINGER
POINTING TO GOD!

The Heavens reveal the power of God
To everyone living on earth;
But then the good news of the gospel must come
From those who've experienced new birth. -- Sper

HIS ETERNAL POWER: e te aidios autou dunamis: (16:26; Genesis 21:33; Deuteronomy 33:27; Psalms 90:2; Isaiah 9:6; 26:4; 40:26; 1 Timothy 1:17; Hebrews 9:14)

Eternal (126) (aidios) means everlasting and is used elsewhere in the New Testament only in Jude 6. Both the unchangeableness and omnipotence of God (see discussion of His omnipotence) are here in view, as exhibited in creation. The Creator, who made all that we see around us and constantly sustains it, must be a being of awesome power.

Power (1411) (dunamis - words derived from the stem duna— all have the basic meaning of “being able,” of “capacity” in virtue of an ability) refers to inherent ability, the power or ability to carry out some function, the potential for functioning in some way, the power residing in a thing by virtue of its nature. It conveys the idea of effective, productive energy, rather than that which is raw and unbridled. God's dunamis has always existed.

From a paper by B B Warfield in Jan,1889 on Darwin's arguments against Christianity:

The history of the drift by which Mr. Darwin was separated from faith in a divine order in the world, divides itself into two well-marked periods. The first of these, which was completed at about the time when he reached his fortieth year, ends with the loss of his Christianity. During the second, which extended over the remainder of his life, he struggled, with varying fortunes, but ever more and more hopelessly, to retain his standing at least as a theist. At the end of the first he no longer believed that God had ever spoken to men in his Word; at the end of the second he more than doubted whether the faintest whisper of his voice could be distinguished in his works. He was never prepared dogmatically to deny His existence; but search as he might he could not find Him, and he could only say that if He existed He was, verily, a God that hides Himself.

For an interesting article on whether Darwin's had a so called deathbed conversion (click here)

AND DIVINE NATURE: kai theiotes: (Acts 17:29; Colossians 2:9)

Divine nature (2305) (theiotes theiotes from theos = God) usually refers to performance that one might properly associate with a divinity. Theiotes emphasizes the divine nature and properties or the whole of that which goes to make up our idea of God. In a sense theiotes is a good summary term for the attributes which constitute deity, signifying  the sum-total of the divine attributes.

Theiotes describes the quality of theos and corresponds more to Latin divinitas from divus, divine. It refers to the quality or characteristics pertaining to deity and thus refers to divinity, divine nature or divineness.

Theiotes could be translated divine majesty and is seen supremely in Jesus Who uniquely bears the divine image (cf. 2Cor. 4:4; see note Hebrews 1:3). He is God’s full revelation in human form (see note Colossians 1:19; Colossians 2:9). The wonderful truth of the gospel is that fallen mankind, through faith in Christ, will share Christlikeness (cf. note Hebrews 12:10; 1John 3:2). The image of God in humanity (cf. Ge 1:26-27) has been restored!

Theotes is the Divine Personality and theiotes the Divine Nature and properties

Wuest writes that...

The Greek word translated “Godhead” needs some study. It is theiotēs. We will compare it to theotēs (also translated “Godhead” a.v.) in order to bring out its meaning more clearly. Theotēs is used by Paul in Colossians 2:9 (see note) where he speaks of the fact that in our Lord “there is permanently at home all the fulness of absolute deity bodily” (in His incarnate state).

Trench comments,

St. Paul is declaring that in the Son there dwells all the fulness of absolute Godhead; they were no mere rays of divine glory which gilded Him, lighting up His Person for a season and with a splendor not His own; but He was, and is, absolute and perfect God.”

Commenting on the use of theiotēs in Romans 1:20, he says,

St. Paul is declaring how much of God may be known from the revelation of Himself which He has made in nature, from those vestiges of Himself which men may everywhere trace in the world around them. Yet it is not the personal God whom any man may learn to know by these aids: He can be known only by the revelation of Himself in His Son; but only His divine attributes, His majesty and glory … it is not to be doubted that St. Paul uses this vaguer, more abstract, and personal word, just because he would affirm that men may know God’s power and majesty, His divine power (2Peter 1:3) from His works; but would not imply that they may know Himself from these, or anything short of the revelation of His eternal Word. Motives not dissimilar induce him to use to theion rather than ho theos in addressing the Athenians on Mars Hill (Acts 17:29).”

Vincent says,

Godhead expresses deity (theotēs). Theiotēs is godhood, not godhead. It signifies the sum-total of the divine attributes.

Thus, through the light of the created universe, unsaved man recognizes the fact that there is a supreme Being who created it, who has eternal power and divine attributes, a Being to whom worship and obedience are due. This is the truth which unsaved man is repressing. Herein lies the just condemnation of the entire race, since it has not lived up to the light which it has. This, Paul says, renders man without excuse. (Wuest, K. S. Wuest's Word Studies from the Greek New Testament: Eerdmans or Logos)

Vine notes that theiotes is

used here only in the New Testament, is associated in meaning with theotes, Godhead, which is used only in Colossians 2:9 (see note). There is, however, a certain distinction in meaning and accordingly the former is here translated “divinity” and the latter “godhead.” The difference in the words is appropriate to the respective passages. Here Paul is speaking of the revelation which God has given in nature of His divine attributes. Man can thereby know certain facts about Him, such as His divinity, but cannot know God personally. Such knowledge can come only through the Son of God (cp. Jn 17:25 with Jn 1:18). In Colossians 2:9 (see note) Paul is speaking of the absolute Godhead of Christ, the fullness of which dwells in Him, and not of an external revelation of His divine attributes. Hence the suitability of theotes, deity, in that verse. (Vine, W. Collected writings of W. E. Vine. Nashville: Thomas Nelson or Logos)

HAVE BEEN CLEARLY SEEN (continuously beheld fully, distinctly apprehended): kathoratai (3SPPI):

Clearly seen (2529) (kathorao from katá = down or an intensifier + horáo = see and perceiving) literally means to look down, see from above, view from on high. The meaning is then generally to view or to consider. The idea is to acquire definite information with focus upon process of perception but associated with an intellectual apprehension. It means to behold fully, distinctly apprehend clearly see and discern clearly. This is the only NT use.

The present tense indicates they are continually on display to be (passive voice) perceived. It is not as if God gives rebellious, rejecting mankind one brief peak as His glorious handiwork that is indisputable proof of His existence.

Vincent observes that...

We have here an oxymoron, literally a pointedly foolish saying; a saying which is impressive or witty through sheer contradiction or paradox. Invisible things are clearly visible.

Theologians refer to this revelation as natural or general in contrast to the Scriptures which are classified as "special revelation" (click and scroll down for more discussion) God’s natural revelation of Himself is not obscure or selective, observable only by a few perceptive souls who are specially gifted. His revelation of Himself through creation can be clearly seen by everyone.

The upshot is that no one has an excuse to say I see no evidence for a Creator, for a God. It takes a deliberate act of one's will to observe the design we see in creation and not acknowledge a Designer. Conscience and Creation is enough evidence to condemn every man. The people who should be shouting the loudest are scientists and doctors who look into the telescopes and microscopes. They see the design and order and plan. When you go to the art gallery and a beautiful painting, you may not necessarily know the name of the artist who painted it but you are certain from the beauty and form and design that the artist was clearly a master.

Adrian Rogers tells of a man who owns a trucking company in the south where part of the hiring process is a lie detector test on which one of the questions is “Do you believe in God?".  They have observed that even avowed atheists who answer this question "no" are shown to be liars by the lie detector!

The stars in their courses proclaim the great Creator's power

Forever singing as they shine,
The Hand that made us is divine. (Joseph Addison)

Napoleon, on a warship in the Mediterranean on a star-lit night, passed a group of his officers who were mocking at the idea of a God. He stopped, and sweeping his hand toward the stars, said,

Gentlemen, you must get rid of those first!

Men secretly believe there is a Power above them, and that their evil deeds deserve the wrath of that Power. In sudden peril, they scream like the guilty wretches they are, "God have mercy!" Knowledge of God, though not acquaintanceship with Him, lay behind Pharaoh’s words, "I have sinned against the LORD your God and against you." (Ex 10:16) behind the words of the Philistines in 1Sa 4:7,8; 5:7,8,11;  and the proclamation of the King of Nineveh (Jonah 3:7-9).

George Washington Carver (1864-1903) chemist and educator wrote that...

Nature is an unlimited broadcasting station, through which God speaks to us every hour, if we only will tune in.

BEING UNDERSTOOD THROUGH WHAT HAS BEEN MADE: tois poiemasin nooumena (PPPNPN):

Understood (3539) (noeo from noús = the mind, reflective intelligence, the organ of mental perception and apprehension) has the with a basic meaning direct one's mind (nous) to a subject.

Noeo then comes to denote a clear perception, a full understanding, and careful consideration. It means to grasp or comprehend something on the basis of careful thought and thus to perceive, apprehend, understand or gain an insight into.

It means to perceive with reflective intelligence and is distinguished from the mere act of seeing because it represents perception of the mind consequent upon seeing. It means to think over a matter with care and so to think about carefully and to consider well.

The present tense indicates that this understanding is continuous and so continuously available to all who have eyes to see and ears to hear. The grandeur and wonder of nature give ample, eloquent testimony to the eternal power of God. The creation delivers a clear, unmistakable message about God’s person which everyone can understand.

Noeo is used 14 times in the NT...

Matthew 15:17 "Do you not understand that everything that goes into the mouth passes into the stomach, and is eliminated?

Matthew 16:9 "Do you not yet understand or remember the five loaves of the five thousand, and how many baskets you took up?

Matthew 16:11 "How is it that you do not understand that I did not speak to you concerning bread? But beware of the leaven of the Pharisees and Sadducees."

Matthew 24:15 "Therefore when you see the abomination of desolation which was spoken of through Daniel the prophet, standing in the holy place (let the reader understand),

Mark 7:18 And He said to them, "Are you so lacking in understanding also? Do you not understand that whatever goes into the man from outside cannot defile him;